Sangheili

The Sangheili are a sapient species of sinewy, bipedal sauroids. As a founding species and primary ruling class of the Covenant alongside the San'Shyuum, the Sangheili are one of the oldest active spacefaring species in the Orion Arm.

Evolution and prehistory
The Sangheili evolved as nimble ambush predators, relying on their agility and speed in short sprints to catch their prey. This strategy differs from early humans and hominins, who used persistence hunting as their primary predation strategy, outrunning otherwise faster opponents over long periods of time. Consequently, while they are much faster and stronger than humans, the Sangheili's stamina and means of thermal regulation in sustained exertion are not as effective (for example, they do not perspire). Their impressive physical prowess is less of an indication of an apex predator role, but rather the harsh and competitive evolutionary environment of Sanghelios, where they are a lower mid-tier predator at best, having sacrificed strength and size for brain capacity. Their primitive cousins would often be forced to resort to scavenging rather than hunting for live prey, although as they grew more intelligent, their hunting strategies also diversified, and with pack tactics they could best even far physically superior prey. It was also around this point that they transitioned from primarily quadrupedal to bipedal locomotion, first intermittently and later near-exclusively. This transition did come with some loss in speed, causing the Sangheili's hunting tactics to be increasingly ambush-oriented. Pack hunting formed an integral part of the Sangheili's formative millennia, and is suspected to have been a key contributor to their development of language and intelligence. Indeed, in more than one early Sangheili civilization, their word for themselves translated to "hunters" or some close equivalent. The early Sangheili organized themselves into tight-knit tribal units in which eggs were brooded and young raised communally - early predecessors to the species' later standard group families and clans. Depending on the latitude, the proto-Sangheili were crepuscular or metaturnal, hunting for food in twilight or in sporadic intervals throughout Sanghelios' somewhat atypical day-night cycle. One contributor to the Sangheili's evolution toward civilization may have been changes to Sanghelios' climate, which gradually cooled while the Sangheili were still evolving to their current state. This allowed the proto-Sangheili to settle new regions and operate increasingly during the day.

The Sangheili believe that they were once a client species of the Forerunners, proudly serving as warriors for the ancient civilization. This narrative was thoroughly ingrained in their mythology and religious beliefs from early on; the Sangheili believed themselves to have been specifically blessed by the Forerunners, making the San'Shyuum Reformists' appropriation of holy technology all the more blasphemous to the Sangheili as the two species first came into contact. The presence of many Forerunner relics on and near Sanghelios suggests there may be some basis in these myths; several bodies in the Urs system (including Sanghelios' own moons) likewise have unnatural characteristics that hint at prehistoric planetary engineering. The presence of the Shard of Heaven - a Forerunner space station believed to have been involved in holding the moon of Suban from decaying in its orbit- in Sanghelios' sky is suggested to have been constructed by the Forerunners in return for the Sangheili's service as Forerunner levies, and a potent gun to hold against the planet should the Sangheili have rebelled against their overlords. Even as the doctrine of the Covenant religion developed to be far more inclusive, with the belief that all species active in the modern era were chosen for their respective roles by the Forerunners, the Sangheili's narrative of their own exceptionalism took ages to fade, and in some ways never truly vanished.

Regardless of the extent of their dealings with the Forerunners, Sanghelios is littered with traces of past civilizations, some of which evidently predate the Halo's firing. Still, it is apparent that the Sangheili returned to a paleolithic-equivalent lifestyle following their reintroduction to their homeworld. This was likely not by choice, but due to the challenges involved in the Conservation Measure, which appears to have reset all known species to a primitive state. Rather than a rapid agricultural revolution and shift to a sedentary lifestyle, the Sangheili's path to civilization began with a long pastoralist phase that lasted for tens of thousands of years before the invention of crop cultivation. The original shift to pastoralism was partly motivated by over-hunting in some regions, where the Sangheili's intelligence allowed them to thrive. Meanwhile, crops were and continue to be grown largely to feed livestock due to the Sangheili's mostly-carnivorous diet. Innovations in agriculture over several thousand years enabled the early Sangheili to support larger and larger communities.

Early civilizations
Partly due to the species' territorial preferences and the harsh seas of Sanghelios making intercontinental travel difficult, the Sangheili only fully spread across their planet when the development of civilization was already well underway (roughly corresponding to humanity's Neolithic Revolution), with most of these great explorations and migrations being launched by the first large Iron Age-equivalent empires.

Biology
The Sangheili are tall, four-limbed bipeds of a taxonomic clade dubbed by human xenobiologists as Cardomandibulae. These are part of a class of reptile-like organisms characterized by their distinctive quadruple jaw structure. One of the most successful forms of being to arise on Sanghelios, the Sangheili's biology has various parallels to terrestrial saurians, though as they are independently-evolved aliens, most of these similarities are merely superficial. The Sangheili's closest surviving evolutionary relatives (equivalent to Earth great apes) encompass several species of land-based or semi-amphibious scavengers and ambush predators, some of which are quite intelligent.

The Sangheili are long-lived by the standards of most known species, living up to around 180 Earth years with a modern diet and medical amenities. They reach reproductive maturity at 23 to 25 years, though they are generally considered youngsters up until forty or fifty years of age. Experience does play a role in one's perception by others, however, and grizzled veterans of many campaigns are generally respected regardless of age. Their long lifespans also mean the Sangheili are capable of taking up many different roles over the course of their lives. While most male Sangheili undergo a period of military service upon reaching adulthood, ranging from around five to twenty years depending on the unit, those who do not go on to become warriors for life are still able to enjoy long careers in their trades of choice. Even warriors from many respected orders such as the Zealots assume many non-combat duties over the course of their lives, particularly in times of peace.

Likely because of evolutionary pressures, the Sangheili have evolved to be terrific sprinters even under the somewhat-higher gravity of their homeworld. Their lean, light build is coupled with their double-heart anatomy, which can pump a lot of oxygenated blood needed during periods of vigorous activity. While this can be sustained for long periods of time if needed, healthy Sangheili have very high energy needs. Both of these are affected by temperature, as the hotter their body temperature is, the faster and more active they become, and the more calories they need to consume. This can cause problems as they do not have efficient means of cooling themselves off. As they tend to stay hot after warming up, many individuals to suffer from heatstroke if they are not given an external source of cooling or extended periods of rest. On the other hand, due to Sanghelios' warm climate and their mesothermic biology, Sangheili are quite sensitive to cold weather.

Sangheili vision is highly developed. Their eyes are most sensitive to variations in the blue-to-violet range, including several wavelengths humans classify as ultraviolet; this may be partly due to most Sanghelios plant life having evolved to use retinaldehyde (rather than chlorophyll) as its photosynthetic pigment, lending it a purple-pink coloration. On the other end of the spectrum, they see a range of reds and browns, but their ability to distinguish between shades of green, orange and yellow is poorer than that of humans. This is one reason for the Covenant favoring violet hues in their architecture, ships and equipment, which are designed primarily with the Sangheili's tastes in mind; the bright purples and bright actinic lights appear to them pleasant rather than garish. Spaces primarily inhabited by the San'Shyuum, such as the tower districts of High Charity, have toned-down lighting and muted color palettes due to their different preferences.

The Sangheili undergo phases of moulting as they age, shedding the outer layers of their scaly skins to make way for freshly-grown skin. The most prominent moulting occurs around adolescence as they grow into their "adult" skins, with the skin remaining flaky and rough for some time.

Diet
The primitive Sangheili were opportunistic hypercarnivores, favoring animal-based nutrient sources ranging from sea life and insectoids to other sauroids, but depending on the availability of food, they would occasionally supplement their diets with fungi and algae. Most of their plant-based needs are absorbed through their predation of herbivores, and when this isn't enough, they consume a few select fruits and roots. Their modern vegetable selections are significantly more diverse than they have been in the past, owing to developments in agriculture, cooking, and the Sangheili's growing tolerance of them. Still, as a general rule, plant-based sources form only a fraction of the modern Sangheili diet due to the ready availability of animal-based sources, mostly being added into dishes for flavor. Sanghelios lacks direct equivalents to terrestrial grain, and their staple crops are most akin to roots, legumes and algae, as well as some types of cave-based fungi. The bulk of the crops on Sangheili worlds are farmed to feed either livestock or client species used for manual labor (often Unggoy). The most common livestock they farm are Colo, a quadrupedal mammaloid, along with various forms of sea life, gastropods and large insects.

Facial anatomy
One of the Sangheili's most distinctive morphological characteristics is their quad set of hinged mandibles. Many related species on Sanghelios share this trait, which originally evolved for feeding purposes while the species' ancestors were still quadrupedal and largely unable to use their forelimbs for feeding. The mandibles, much stronger and more prominent at the time, were used to both immobilize and kill prey as well as guide it into the mouth. On some related species, the lower pair are much larger than the upper one, and serve a pincer-like role. The modern Sangheili's smaller mandibles are actually a neotenic trait retained from an ancestral mutation at one point in the species' evolution. Normally, as their ancestors would mature into adulthood, the mandibles would grow considerably larger. However, this would also directly limit the brain size, as the muscles responsible for moving them took up considerable space around the cranium. This can be seen with several of the species' surviving relatives, which retain a thinner, elongated skull, with some even having an additional head crest to which the muscles attach. As the species shifted increasingly from quadrupedal to bipedal locomotion and began using the forelimbs to manipulate objects, the need for the mandibles for their original purpose grew less acute, and the retention of the more neotenic, less pronounced and weaker mandible structure freed up space in the cranium for a larger brain to develop. Now, the mandibles are largely vestigial and only have limited utility in their original function; their most notable use is as one of the Sangheili's primary means of conveying expressions.

There exists some variety in the shape and size of the mandibles between different Sangheili ethnic groups and, to some extent, individual phenotypes. Because of their evolutionary history, larger and more forward-jutting mandibles exhibited by some phenotypes are generally seen as more atavistic or "primitive" traits in Sangheili. An interesting trait which once manifested in the Quun, a now-extinct subspecies of Sangheili, is the fusing of the two mandibles on each side into one, while retaining the quadruple bone structure; similar developments can also be seen in other extant members of their clade. As the subspecies could interbreed by what are now regarded as Sangheili, vestiges of this trait still manifest in some isolated population groups.

Another atavistic trait still seen in some Sangheili are low, sloping forehead ridges, whereas comparatively prominent brow ridges (a byproduct of the larger cranium) are a more modern morphological characteristic.

Physiological variety
Though there are numerous Sangheili ethnic groups, on a broad level, the Sangheili divide their species into several major ethno-linguistic groupings known as phyles, also translated as "tribes". These are marked by physical distinctions and are based on mytho-historical views of the species' ancient past on their homeworld, with each phyle being assumed to have its own legendary heroes and founder figures, for example. That said, they have not fully mapped to subsequent ethnic or political divisions for millennia, and their physical markers have become less relevant in many mixed populations.

The following lists the twelve most commonly recognized phyles along with the Sanghelios continents they originated from:


 * Qeremu - Qivro/Yermo
 * Washanga - Qivro
 * Sarti - Qivro
 * Yermi - Yermo
 * Jaraati - Yermo
 * Chiwaka - Tolvuus
 * Tuwala - Tolvuus
 * Kelechu - Tolvuus
 * Kharsi - Kaepra
 * Ijuuno - Kaepra
 * Nurias - Kaepra/Vaardma
 * Quun - Vaardma (typically divided into the Ir-Quun and Sar-Quun subgroups)

Psychology
The Sangheili have an innate drive for physical activity, especially the competitive kind. Should they be deprived of regular opportunities for physical exercise, Sangheili tend to grow irritable and nervous, though the severity of this effect varies by individual and life-stage. The Sangheili will also fall out of shape relatively fast without regular exercise, and the negative physical and psychological effects of a lack of exercise are much more pronounced than in humans. As a result, an emphasis on athleticism and sports is a universal fixture of Sangheili culture stretching back to their earliest civilizations. Coupled with their competitive drive, this most notably manifests in their martial culture. Outside the field of battle, a sizable industry exists for substituting warfare, in the form of exercises, martial arts, tournaments, sporting competitions, hunting, tracking, orienteering and many other outdoors activities. Certain sports also have important socio-cultural and even religious roles. It is not uncommon for lesser clan feuds to be resolved by team sports styled as ritualized combat, and there are sporting events that double as religio-cultural rituals in many Sangheili societies, including that of the overarching Covenant superculture.

Although the Sangheili require sleep, they are also capable of a half-conscious rest state akin to the unihemispheric slow-wave sleep that occurs in some terrestrial fauna. This capability, in which only one hemisphere of the brain is "asleep" at a time, evolved as a vital part of the Sangheili's ambush predator strategy, allowing them to be both alert for prey and threats while remaining immobile for long periods at a time. Although many of their evolutionary relatives are able to forgo "full" sleep altogether, as sapient beings the Sangheili still require full dormancy periodically. Their ability to stay half-conscious is useful during long deployments aboard warships or during guard duty, but the longer they put off complete rest, the longer they also need to sleep to recover. Due to this quirk, many Sangheili tend to underestimate other species' needs to sleep, leading to their subordinates (Unggoy in particular) often napping while on duty.

Culture and society
Compared with most of the other species, the Sangheili exhibit remarkably stable social and cultural institutions, which change only with the passage of centuries, even millennia, unless forced by upheavals. Part of this owes to the Sangheili's relatively long lifespans making their generations longer. Trends in Sangheili societies are communal families, emphasis on physical and mental fitness, and various martial or sporting activities.

The Sangheili widely treasure the ideal of completely devoting oneself to one's art and eventually mastering it through lifelong self improvement. This may be warfare, sculpture, poetry or any of the arts regarded as noble. This ties to their philosophical belief about becoming sovereign and free of outside restrictions; where one not only has mastery but brings something new into the world.

One's word, personal discipline, integrity and honor are almost invariably the pillars of Sangheili society, but how these cornerstones are observed or understood varies by region. Honor is a complex social commodity to the Sangheili and drives much of their endeavors from micro to macro levels. That said, how these rules worked in practice has varied vastly across time. Periods of peace have often led to increasingly impractical rules becoming fashionable among clans, while those who were forced to wage serious war usually adopt more functional customs out of necessity.

There is an underlying theme of contrasting periods of stillness and bursts of rapid action in Sangheili culture, including theater, literature and philosophy. This undercurrent has been attributed to their ambush predator origins.

Notably, the cultural information listed here describes trends rather than practices followed by all groups of the species. The intent is to provide an overview of archetypal aspects of Sangheili culture, along with more specific examples, but individual cultural groups do not always exhibit all of the traits and practices listed here. Still, a certain degree of cultural hegemony, especially in martial matters, is exerted within the ministerial institutions of High Charity, which in turn are influenced by the prevailing cultural mainstream on Sanghelios as well as Covenant-wide trends.

Meritocracy
The Sangheili prefer to see their society as a meritocratic one, though this ideal manifests in different societies in various ways, sometimes being stronger than in others. Sangheili cultures generally vary on two main axes: individualism vs. collectivism, and meritocracy vs. family ties. Most cultures fall somewhere in between the extreme ends of these spectra. Typically, individualism is tied with meritocracy while collectivism relates to family ties. It should be noted that very few Sangheili societies understand individualism the way humans typically do; most of them still put the household and culture at large before the individual and emphasize one's duty; but individualism is understood in the sense of the individual's self-realization and imposing one's will on the world.

There are differences in how the ideal of meritocracy factors into social mobility on the micro and macro scales; namely, how the meritocratic ideal is applied on the individual, family, and species levels. Most notably, the meritocratic ideal has led to the implementation of universal exams for entry into various societal positions. Anyone regardless of family background is able to partake these exams, though in practice aristocratic and wealthy households are in an advantaged position as they are capable of investing more to the early education of their offspring. However, commoners with sufficient determination (and sometimes powerful patrons) are also capable of excelling in these exams, which may in turn elevate their status to nobility later in life.

Overall, the Sangheili view (which has in turn influenced Covenant philosophy) is that every species should be doing what they are best at (or, rather, what the higher castes deem them to be best at). But to an extent, this also applies on the scale of sub-populations, worlds, clans, and families. If a clan is known for their artisans or merchants, then that clan is expected to specialize in those occupations. Occasionally, very skilled, ambitious and well-noted individuals can change the perception of their entire clan or world, which in turn influences their future course. In theory, this applies to all species, but in practice the gamut of jobs available to Unggoy or Kig-Yar in the first place is narrower, and several high-caste jobs (e.g. artisans, politics and military command) are obviously restricted from them. Commercial roles are something of an exception, but while they sometimes go hand in hand, economic and societal prestige are still two separate categories within the Covenant.

One's status in the feudal hierarchy also affects one's opportunities in the military. While it is possible for commoners to rise up fairly high, in accordance with the ideals of meritocracy, in practice they must often take up less desirable posts such as non-combatant duties, or ones with much honor yet a high casualty rate. This is at least in the beginning, until they have a chance of proving themselves.

System of nobility
On the surface, the notion of a hereditary aristocracy as a fixture of Sangheili society appears to conflict with their meritocratic ideal. Indeed, not all Sangheili lineages across the Covenant even have a distinctly defined aristocratic class; such cultures being in the meritocratic end of the scale.

Because of the prevalence of lesser races increasingly responsible for low-level work in most societies of the Covenant, aristocracies of the pan-Sangheili civilization became more or less enormously bloated during the Covenant's reign; former commoners gradually passed into nobility through increasingly small accomplishments in a system originally designed to be in keeping with the Sangheili's meritocratic ideals. Though war was always the most surefire way to advance, in periods of peace the advancement was often precipitated by the closest equivalents - tournaments, sports competitions and wargames among them. Other paths existed as well - statesmanship, community kudos, artisanship, literature, poetry and the arts, athleticism, other remarkable contributions to society such as expeditions and the discovery of new worlds or slipspace routes, and more.

Of the nobles, the vast majority occupied the lowest tiers of the aristocratic ladder, some of them little more than honorary titles and others only temporary — which is also seen to be in keeping with the ideal of meritocracy. Even so, there remained a sizable commoner class, a little over 60% of the overall Sangheili population with more specific percentages depending on the location. This, in turn, accelerated the expansion and more importantly, internal subdivision of the Covenant, with individuals of the increasingly bloated noble class claiming their own micro-states within the empire's territory.

Sangheili commoners' ways are informed by the same social framework as that of the nobles, but also vary in many ways, sometimes substantially. Most notably, they tend to be even more community-driven. Commoners who enlisted in the military usually began with a low rank in skirmishing units, while those who showed promise would be tasked to lead a lance. After their term of military service, particularly distinguished fighters who chose not to continue their service were usually given a lesser noble title and a patch of land.

In keeping with the overarching concept of meritocracy, even longstanding nobles could also lose their status. Usually this happened due to shame resulting from failure, cowardice, crime, or various other shameful acts. An inability to perform in certain initiation rites required of nobility, or other sources of shame, may result in one's status being lowered as well as banishment from one's keep.

Views on governance
In the general Sangheili mindset, a good leader must be able and willing to protect his people; for political power is heavily tied with the physical kind, but they are not synonymous, as in more tribal cultures such as that of the Jiralhanae. A good leader must also possess other virtues, such as wisdom and cunning, and possess skills in diplomacy and statecraft. But in general, it is difficult to find a Sangheili political leader who is also not some manner of fighter or general, at least in background. Exceptions have been made, but the trend stands. The optimal ruler is one who is both wise but strong; a warrior and a poet; a philosopher and a king. This in turn refers to old esoteric philosophical ideas of a Sovereign King or Heavenly King, one who is a complete master of one's own destiny, and the destiny of his people; one who is able to impose his will on the world as he wishes yet not be consumed by his supreme power. He is stoic and only ruled by his own will, not of the laws of the world. Good leadership is all about a balance of different virtues, from the physical to the mental to the esoteric. More often that not, it is not a perfect balance, but rather excesses in one or two areas compensate for deficiencies in others.

Sangheili in leadership roles are usually older, past their initial stint of military service, and serve as advisors and administrators, known as seneschals, in households and estates.

Universal democracy is not highly valued among Sangheili; while many societies do have elected rulers, suffrage rests on a privileged few, and Sangheili generally regard universal suffrage as the height of folly; for only those who have demonstrated virtue and skill are deemed fit to choose their leaders. Meritorious deeds and status bring with them more political power. Even in the most democratic Sangheili societies, not everyone usually has a vote, and the voting power one has increases as they accrue merit and distinction. For example, a decorated veteran may have seven votes where someone who just completed their first tour would have only one.

Honor and ethics
Sangheili honor is a complex system of reputation and social etiquette closely tied to their systems of merit. One's honor affects everything, including progress throughout life, and one particularly egregious blunder can ruin one's reputation for life. What is easily seen as a monolithic system by outsiders is in fact a complex interplay of various customs and practices. Many of these practices are shared to an extent within the greater Sangheili meta-civilization of the Covenant, though more particular rules are more localized to certain domains, worlds, or even singular clans. Notably, rigid codes of honor are generally more diligently followed among nobles than commoners, and are particularly strict in elite warrior orders such as the Zealots; though commoner Sangheili do have systems of honor, they are generally more basic and lenient.

Sangheili warrior ethics are complex, variable, and not easily transposable to simple good-and-evil dichotomies. There is also a way one is expected to conduct oneself that further varies according to their position in society, gender and trade. Most Sangheili are expected to observe an ideal of "restrained boldness" wherein one avoids showing overt weakness and carries oneself with a quiet, proud dignity. While mainly built for warriors, these virtues (or variants thereof) carry throughout society and are held up as ideals; warriors are respected because they are thought to embody them the best.

One of the most popular sources of commonly-observed rules, aside from family traditions, is the Huuran'asii, freely translated as the "Righteous Way". While now regarded as an ancient way, as a singular document the Code is actually rather recent, dating back to the ages after the Second Illumination some seven centuries before the present. While many of the ideas listed in the Code are ancient or at least very old, they have variable origins and have historically not been seen as a singular set of rules; additionally, several are likely post-Second Illumination additions or based on romanticized views of Sangheili warriors in the preceding Feudal Era, popularized by numerous epic poems and songs. Regardless, the Warrior Code is now the most popular reference for universally-agreed upon rules aside from the unique customs and practices of clans.

According to the Code, a warrior should not be a brute, nor is any fighter or soldier automatically a warrior. Rather, a warrior is one who has mastered his own destiny and in this channels a bit of the divine in himself. To do so, one must also be cultured and intelligent - a "warrior-philosopher" or "warrior-scholar". At the apex of this axis lies the scholar-king, one who has mastered his own way and can command loyalty from entire peoples.

Strength is a virtue, but this is understood as being a strength of both body and mind, for the two are seen as a whole. A weak mind in a strong body is as good as a brute. It is not strength to be cruel and dominate senselessly, nor waste lives (including one's own) on unworthy causes. A death for death's sake, even in battle, is wasteful rather than glorious. Vanity is a great weakness; one must have the boldness to stand up for oneself, but never to boast or try to prove oneself in the eyes of others. Thus cunning, as well, is seen as a strength, for a warrior must know when it is the right time to strike and when to stay one's blade, and fight battles of intrigue instead. One who is merely bold and strong but without wisdom is foolish. Likewise, while war is generally regarded as glorious, bloodshed for its own sake or for an unworthy cause is dishonorable, as it is the way of barbarians. This latter part is often particularly emphasized by Sangheili when comparing themselves to the Jiralhanae. The increasing prevalence of the Jiralhanae in Covenant society over the past centuries and especially recently has led to many members of other species drawing parallels between the martial-focused cultures of the Sangheili and the Jiralhanae. This bothers most Sangheili, and has made them more conscious of their own cultural identity as a collective. In practice, this has led to integrity, honor, and nobility being far more emphasized in Sangheili society than they may have been before, as the Sangheili claim these traits set them apart from the Jiralhanae.

Honesty is a virtue, though its corresponding vice is naivete and gullibility. To Sangheili, one's word is all; one's word or oath, when given, should rightfully be synonymous with action unto itself. Likewise, if one betrays his word, he loses any credibility he may otherwise have had on other matters as well.

All these virtues exist on a spectrum from virtue to vice; each has a corresponding reflection, which is not always a direct opposite but the virtue pushed to an extreme. That said, the code is more the ideal than the reality, and one can find Sangheili in both ends of the spectrum, from those who follow the code to the letter to those who practically ignore it. Following the Great Schism, some extreme reformer Sangheili have cast even the Code in doubt, seeing it merely as another outdated relic of the Covenant's ways.

Accordingly, the Sangheili put great emphasis on proper conduct in warfare. Some of these rules are formalized as a system known as Shal'annu, a doctrine that seeks to limit excesses in war. While Shal'annu originates in the pre-Covenant era, it has since come to encompass virtually all inter-Covenant conflicts. Such rules are rarely applied to external wars, whose the use of force is chiefly dictated by brutal efficiency.

Bioethics
There persists a common human misconception that Sangheili shun all medical treatment and doctors, but these rumors are at best heavily exaggerated. It is true that many warrior traditions are rather particular about acceptable medical procedures; however, this is entirely dependent on context. Medical treatment is not shameful in and of itself, as warriors are expected to ensure they are in top fighting condition at all times. However, warriors may have a certain threshold for seeking out medical aid when it comes to lesser injuries, as any form of malingering is regarded as extremely shameful. Those who are regularly injured as a result of carelessness or foolishness are also widely looked down upon. The most hardline views regarding medical treatment can be found in certain Zealot orders, which take otherwise-moderate traditions to their logical extreme.

Medical practice is also heavily regulated, and is widely seen as a feminine profession. Exceptions exist for the battlefield, and virtually all Sangheili are trained with first aid (though this may also mean a quick death rather than evacuation, since Covenant attitudes about death are rather cavalier). Thus, most Sangheili doctors or healers are female and belong to any number of monastic orders, of which the Rennai sisterhood is the most prestigious and respected.

Mainstream Sangheili society does, however, frown upon cybernetics, bio-augmentation, and genetic engineering. Prosthetic or regrown limbs and organs are generally accepted when it is necessary to replace body parts lost in battle, but some individuals have been known to forgo replacements, especially of non-essential body parts, to flaunt their prowess or toughness to others, or as a personal reminder of one's own mistakes. Cybernetics and bio-engineering used for the purposes of enhancing one's natural abilities, or replacing intact body parts, are much more of a taboo. There is an overarching belief in the sanctity of the body and mind, and the value of improving one's prowess through one's own achievements rather than artificially inducing it with technology. Covenant history knows several cases of movements seeking to challenge these long-held preconceptions (such as the Sha'vakan marauders), but such groups have at best been ostracized by society at large, and destroyed as heretics at worst. Low-key enhancements, such as medical therapies to endure radiation or various other detrimental phenomena in space, are the exception to this, but thanks to the various technological conveniences of latter-day Covenant society, such things are largely a thing of the ancient past.

Military and civic service
Most Sangheili males undergo a period of military service upon maturation, a near-universal tradition arising from ancient coming-of-age rituals and understood as an individual proving their value to the community. The expected length of the tour varies from culture to culture, but it is generally over five years and usually between ten and twenty; all need not serve, but service is typically required for most offices or for any higher status in society, and expected of all males. The female equivalent usually takes the form of civic, religious or community service of one variety or another, though it can have military dimensions as well in e.g. supply and logistics, though combatant roles are rare. The distinction between military, civic guard and paramilitary is not clear, and many civic functions are performed by what most humans would regard as military organizations. There is no set period of service; rather, one must serve for at least one "campaign" or "tour". This is broadly defined as participation in a war or other conflict, or a fleet patrol, but usually requires one to see action at least once. Sometimes this can mean two years of service, other times twenty.

Not all male Sangheili (especially on worlds off the Arterial Network) undergo military service, though the overwhelming majority do, at least in some form. This is a cultural holdover from the Covenant's High Antiquity, when universal conscription into the military of the Covenant proper was still feasible. Now, most Sangheili serve in their house guards or regional garrisons, while only a select few make it to the ministerial armed forces.

Mainline warriors begin their career in communal units known as warrior crèches. Upon graduation from a crèche, warriors are assigned the rank of Minors. Underperforming Minors only serve the minimum stint of active-duty military service, and are expected to find work off the field afterward. In practice, this means moving down a rung on the Covenant social ladder, since being a warrior is the only surefire way to political power and societal prestige. For Sangheili who know they won't choose the path of a warrior for life and instead go on to become merchants, artisans, etc, or non-combatant specialists in the ministerial forces (e.g. pilots, mechanics, etc), this is not deal-breaking. But for those with aspirations (or family expectations) for valor, glory and high status, it can be shameful, which in extreme cases has led to such individuals taking their own lives.

The vast majority of male Sangheili undergo a period of military service but after this, their future is more open-ended. Even many career warriors and members of holy orders like the Zealots serve in civic roles for large chunks of their lives, simply because most of the time there are more warriors than there are wars to fight. But some know their true calling is outside the field of battle, and while those jobs won't land you the most prestigious positions later in life, someone has to do them. Many families already specialize in matters like commerce, industry or the arts, so they don't even have the expectation for their scions to become high-ranked warriors. And unless one is truly inept, there are not very many truly "shameful" jobs for Sangheili out there. It's mostly just about one's own ambitions.

Family and households
Most Sangheili communities favor communal creches or group families of varying kinds. Monogamy does exist, but is the exception rather than the rule. These family structures arose from communal egg-rearing behaviors, which were very common in primitive Sangheili cultures—a direct continuity from similar behaviors among the species' nonsapient and protosapient ancestors.

Sangheili household structures and compositions vary greatly, but almost always encompass more than a single family- often including the extended family, allied clans, subordinate commoners, servants, etc. Households almost always encompass artisans, armorers, weavers, mechanics, and more, with larger clans having veritable armies of such specialists. While most households that are reasonably well-off have at least a rudimentary representation of most professions, there are ones that specialize in certain trades more heavily, which begets trade between them. Typically, the collection of these groups inhabits a keep or a comparable unit, such as a clan spire.

By human standards, romance and sexuality tend to be understated in Sangheili societies, with platonic relationships assuming a larger role. Since this is a recurring trend across time and different cultures, it supposedly has basis in biological factors. Though they recognize various states that can be understood as love, bonding and affection, as well as physical attraction, romantic love (as humans tend to regard it anyway) is, if not absent, at least less socially prominent than it is for humans. The deepest bonds are typically viewed as those between warrior creche peer groups, brothers in arms, or mentor and pupil, for example. Relationships between members of opposite sexes tend to be seen as being utilitarian in nature (with the fitness of bloodlines and political unions being the primary considerations), though these can assume quite deep emotional bonds as well. In general, though, Sangheili find their deepest bonds to a small group (military unit or group family) than a single individual.

Offspring and upbringing
In most cases, Sangheili upbringing is harsh by modern human standards, finding more apt comparisons in the ancient world. Upbringing is regimented and near-constant; from the time the child is able to walk, he or she begins their life-long journey of learning. There is free time for play, but most of the days are spent in training, education and exercise. Beating is a common and accepted, even expected, form of discipline. As a general rule, the higher aristocracy are usually more stringent about their upbringing as well as punishments than the commoners or low nobility, as more is expected of their offspring. Offspring are often sent to the wilderness of wherever they happen to live or even off-world or into space to learn to survive on their own.

Communal creches among like-minded individuals are the most common way of raising offspring, even in the case of monogamous societies; this is in line with the Sangheili's generally meritocratic ideals, as well as the notion of having multiple mentors to pass on wisdom. Within a household, it is rare for uncles or fathers to raise a child directly; instead, that task falls upon the family matrons, elders and mentors, masters of the various arts. As with other matters, the entire household is responsible for the raising of the children. Any adult of the household or of an allied one may discipline a child of a keep as they see fit. In some regions, families send their offspring into other keeps to be brought up to make valuable connections for the future as well as learn perspective through the ways of other families.

Historically and even today, many Sangheili societies have tended to treat those with disabilities or deformities quite harshly. According to prevailing mindsets, physical and moral virtue are intertwined; in simple terms, fitness and beauty are equated with goodness, ugliness and sickness with decadence, sloth and evil. That said, there are nuances to this. Some forms of deformity, such as scars gained during combat, are widely respected even if they are gruesome. Individuals with mild mental disabilities may be able to find work in their household for life, or failing that, be cared for as an act of mercy; but this varies. The infirm may accept various noncombat roles, and many choose to live as monks; procreation is almost universally out of the question. The harshest societies even cast out or euthanize the weak and the disabled, who are not seen as having a place among the strong, though they are often merely left to fend for themselves rather than killed; there are known instances of Unggoy serfs or Kig-Yar spacers raising Sangheili castoffs out of pity. Indeed, the Sangheili tradition of not knowing one's parents is partly based on the customs of infanticide: as parents do not know for sure who their offspring are, they will also be less attached to them. In other cases, individuals with mild physical deformities may be adopted by specific religious orders, such as the Subanite Brotherhood. Some physical infirmities may be able to be mended through medical science, though many societies frown on trying to improve on "weak blood", and families often do it in secret.

The Sangheili place significant emphasis on finding one's "life-calling", the primary focus of an individual' professional and personal growth. Many Sangheili societies have a complex system of familial sub-specialization "rates" by trade and interest-group, separated around early to mid-teens as individuals' skills and inclinations are ascertained. Some amount of combat training is standard since early childhood, based on the ancient notion that everyone should be able to defend the household in the event of an attack. As with every aspect of family life, this varies from culture to culture, and the most stringent of ways are not always practiced outside the nobility; urban or spaceborne cultures tend to be more relaxed or at least varied in their customs.

Higher education
Nearly all Sangheili households provide their offspring with an introduction to their family's history as well as that of the Covenant, as well as basic combat skills, but more wealthy families are able to maintain better scholars and tutors, and teach them everything from poetry to the nuances of language. Certain clans can also be more lax in their training regimens, especially smaller ones more concerned with a family trade, such as farming or commerce. Overall, the stringent expectations and training of noble households typically prepares their offspring for advancement much more effectively than commoner families.

While basic skills, tradition, literacy, values and social conduct are taught within the keep, for higher education, Sangheili attend schools of the trade of their choosing by adolescence. Males enroll within a warrior creche by the time they are able to fight; a form of training unit, this also serves as a young Sangheili's primary peer group for several years before mainline military service, and possible eventual civilian career. Over time, youths within a warrior creche are split into various tracks based on their skills and aptitudes; those most skilled - known as Potentialites - are sent off to war colleges to become officers, while those with lesser leadership aptitudes or more pronounced brutish tendencies become shock troops or exclusively combat-oriented Minors; though even they may later advance through the ranks should they prove themselves. Those whose talents are geared toward creation rather than destruction still do undergo military service in most cases, but usually return to civilian life to pursue their craft of choice at the first opportunity; though others prefer to gather distinction in the military first. Military service was usually the only surefire way for political advancement as war colleges also contain a wide range of other education preparing one for life: high language, religion, history, astronomy and cosmology, arts, politics and statecraft and law. Training is rigorous and constant, and discipline is extremely high. Most of those who go to war college are traditionally nobles, but there are also wealthy commoner merchants or other powerful individuals with the means to prepare their sons for the rigorous entrance examinations. The principle of meritocracy means that most self-respecting Sangheili societies try to arrange nominally equal chances for commoners to advance. As such, there are also schools for commoners. These have more variance in their quality of education, and some (particularly on more wealthy worlds on the meritocratic end of the spectrum) can be nearly as good as the higher academies or cover the same range of topics.

The Sangheili are generally trained and educated in mixed-gender groups up until their mid-adolescence, when the two sexes begin to be more specialized in their future roles in life. Sangheili youths already assume some responsibilities, and may for example aid the local law enforcement, public works or disaster relief in this phase. The next step is usually service in regional garrisons and/or as a steward for a warrior, then assignment to a warrior creche - a kind of communal unit for unmarried males. The female equivalent is some form of formal education, usually accompanied by civil service in a given trade; the ministries of the Covenant also offered some roles available for females. Like their male counterparts, female Sangheili mostly inhabit a communal creche at this stage, before being espoused to a keep-family or equivalent. Those who wish not to marry or are deemed unsuitable have several options; they can devote their lives to the trades acceptable to them, or join one of several monastic orders.

Gender roles
Most Sangheili societies within the species' mainstream meta-civilization have a fairly rigid division of duties and trades between the sexes. However, the specifics of those trades vary by clan, world and region. Sangheili gender roles have also varied vastly throughout history. This is partly influenced by the differences in Sangheili biology and evolution: while it exists, sexual dimorphism is less pronounced than on humans, and the Sangheili lack the multi-month gestation period altogether. Neither is the infant strictly tied to the mother after birth; the rearing of eggs and hatchlings was communal in many primordial Sangheili cultures, practiced by both males and females, which would later gave rise to structures such as the keep. Today, the variety largely reflects the lineage vs. meritocracy axis of the overall Sangheili culture, wherein lineage-focused cultures are more likely to be gender-segregated while meritocracy-oriented ones are more egalitarian and focused on the characteristics of the individual. However, practices on the lineage side of the scale are far more mainstream, and were followed in most of the Covenant's ministerial armed forces.

Generally, equal respect is accorded for each gender (at least nominally), though some division of labor usually exists. Traditionally masculine pursuits are various leadership, military and mainstream religious roles, whereas females tend to focus on civic affairs such as property management, commerce, the sciences and select arts. There is also a nurturing streak associated with the feminine, which has led to doctors being regarded a feminine profession, sometimes exclusively (as with the Rennai). A number of roles and professions (such as various artisans and traders) are regarded as gender-neutral, though there are often different nuances in how the different genders undertake them; poetry, for example, is practiced by both sexes, but its content and societal functions vary by gender. In combat, males are expected to be aggressive and honorable, while females are defensive; this is based on ancient traditions of the women and the young defending their keeps from attack while their warriors were away. In such defensive combat, "fighting dirty" was not merely acceptable, it was expected, which gave rise to the notion of warrior honor being exclusively masculine in nature. Most Sangheili, male or female, do not see this duality and division of labor as wrong. It is simply accepted as a part of the tapestry of life as much as anything else; for there is a strong belief that one should find one's true calling; the world-task one is most suited for, and pursue that task relentlessly until one masters it so perfectly the gods look favorably upon him or her.

As Sangheili females are generally smaller and have less muscle mass than males, the latter have historically been responsible for most combat-oriented duties. Even in societies where females are allowed to serve in combat, the onus is on them to prove themselves should they wish to partake in war. In most Sangheili societies, both males and females do undergo some form of civic or military service, with certain military-attached logistical and specialist roles being regarded as unisex. While relatively scarce in the hegemony's later ages (though this has not always been so), female roles within the Covenant military did exist, though they were typically concentrated on specialist duties such as mechanics, artisans, crafters, weaponsmiths, certain types of pilot, medic, vehicle operator or starship crew. Still, all Sangheili roles within the military require basic combat training.

Where female Sangheili did participate in combatant roles, their units were usually segregated from male ones. Since combat-oriented females in the ministerial armed forces were still a rarity, their units tended to be small and specialized, often being deployed as scouts or outriders of some form. However, more variety was evident outside the ministries and in the numerous martial orders or clan militaries that existed throughout the Covenant Sphere. Females are able to serve in specific organizations of the clergy, though they are almost exclusively part of their own separate orders; one of the more notable ones was the Rennai sisterhood.

In theory, females were not explicitly barred from serving in combat-oriented roles within the mainline legions. Should one fulfill the requirements, they would be allowed in on the basis of meritocracy; however, in practice the environment was such they would have faced considerable systemic prejudice, and so most would not even bother with the trouble. Previously and up to the Covenant's fall, many units had a role where the unit commander had to personally approve of new arrivals. This meant that traditionalist commanders, or those particularly concerned with their reputation, would often deny female applicants; this was either due to cultural prejudice or fear of the unit losing their prestige and honor. Specifically, having females in one's unit was widely regarded as dishonorable because "fighting like a woman" is associated with ignoble, "dirty" tactics commonly applied in the defense of a keep and household, whereas true warriors of the legions must hone their practice of refined and thus "honorable" fighting traditions and styles. This stigma dies hard even though most females who actually did apply for service in the legions have trained in schools of combat accepted as honorable. In some traditions, females who become commanders or warriors are not expected to bear young, though this too has varied with time and cultural context, with the offspring of fighting women either being shunned or glorified.

Arts and activities
In general, the Sangheili tend to frown upon total idleness, and usually occupy themselves with various leisure activities outside their professional pursuits. These include poetry, philosophy, theology, music, as well as numerous types of sporting competitions, hunting and various arts. Persistently and systematically improving oneself in a given art is a recurrent theme throughout these activities. There are some differences between the activities enjoyed by the commoners versus the aristocracy, but typically they follow similar overall themes, and some hobbies are shared by all social classes.

Poetry and song, the distinction between which is not explicit, hold a crucial importance to Sangheili as means of teaching, recounting history, and commemorating past deeds. Warrior aristocrats are expected to know important pieces of poetry and be capable of reciting it in appropriate situations. This is tied to a strong oratory tradition.

Related to their celebration of physical and mental fitness, the Sangheili place considerable importance on cleanliness, which has both mundane and ritual aspects in their culture. Communal bathhouses are a common fixture of communities, usually serving more functions in addition to bathing; they feature gymnasiums, medical and wellness facilities, and often serve as centers of socialization, with events such as dance performances, public debates and speeches. Baths are one of the few spaces in Sangheili society where distinctions of class and gender are understated, being generally unisex and open for commoners and aristocrats alike; however, multi-species baths are rare.

Social organization and politics
Sangheili society is characterized by feudal relationships between myriad polities from the interstellar to the local scales. Relatively small communities often have a high degree of self-determination on most matters, while defense, foreign policy are religious leadership are more centralized. Today, the patterns of Sangheili society and governance pervade the Covenant, and in many ways form the baseline for the alliance's political organization below High Charity. In many ways, modern Sangheili political structures have both influenced the Covenant and developed as a consequence of the Covenant on all but the smallest scale.

Many Sangheili communities are extensions of an aristocratic clan's dwelling, traditionally known as a keep, which exerts some degree of geopolitical and/or economic power. Although they come in myriad forms, a keep is traditionally set up as a defensible and often self-sufficient set of dwellings governed by a ruling noble family. While the keeps of the smallest families are relatively humble, those belonging to powerful aristocrats are massive arcology-fortresses with city-sized populations in their own right. In addition to the ruling nobility, a keep is inhabited by their retainers as well as various lesser families of commoner or low aristocratic rank. Other commoners reside in the surrounding area. Not all Sangheili clan estates fit the traditional definition of a keep, and those in urban settings or in space habitats are often more diverse in their arrangements. In cities, commoners may inhabit buildings or neighborhoods with a degree of internal political organization akin to housing cooperatives. In rural environments, extended families and communes reside in farmsteads or villages. Notably, Sangheili community structures were far more eclectic prior to the introduction of most of the Covenant's servile species, as Sangheili commoners were far more numerous in those times.

The holdings of a keep can encompass farmland, cities, industries and other commercial entities, starships and habitats, and more. As a rule, the keep is expected to be able to take care of its subjects and defend them in times of war; failure to do so will easily lead to the land and those subjects falling under the influence of another keep. While they can be wholly autonomous, most keeps exist in a feudal hierarchy with larger and more powerful keeps' lords ruling over lesser ones. A number of keeps (from a handful to hundreds) make up a state, whose head is defined as a kaidon (analogous to a king). Though their responsibilities vary, a kaidon's rule is not absolute, and they must nearly always balance their own leadership with the interests of a council composed of the lords of their fief-keeps. "State" is used as a generic descriptor rather than a specific type of polity; various types and forms of government exist among the Sangheili. Some states have no single strongly-defined head and supreme executive power rests on more than one prominent lord. Others, particularly urban city-states, have pseudo-democratic arrangements. Outside contributing to defense, the governance of most states is fairly distributed. Though each state has a different way of dividing the responsibilities between the central government and its subordinate units, keeps tend to enjoy a fair degree of autonomy within their holdings.

The politics and borders of these states tend to exist in a permanent state of flux, as lesser keeps or coalitions thereof make alliances or are conquered by more powerful keeps. However, some states manage to maintain relatively fixed borders due to a shared cultural identity and/or political interests, with the oldest states on Sanghelios and the Sunlit Worlds being millennia old. The development of such semi-permanent states originally allowed the Sangheili to embark on mass-scale industrial and logistical efforts, among them the development of space travel. On the other hand, the ensuing space age and the advent of slipspace travel saw governance becoming increasingly decentralized due to the difficulty of directly governing faraway worlds.

Feudal associations or alliances between states may span continents or entire worlds. On many colonies, these associations are in turn governed by a planetary lord who might hold a number of secondary worlds under his vassalage. On Sanghelios and many of the Sunlit Worlds the planetary states are often too historically powerful in themselves to agree to be governed by a single family, though they at times represent themselves to the outside through leagues and alliances — provided they do not have ongoing feuds with one another. The creation of the Covenant led to the decline of many of the larger Sangheili polities as cohesive units, as many functions were gradually adopted by the Covenant's hierarchy. Recently, the Great Schism has seen such polities growing in importance. For example, Sanghelios and many parts of the Urs system are currently governed by the Swords of Sanghelios, a political and military alliance comprising most of the world's influential states.

Metropolitan communities are densely populated, and are archetypically seen as both more progressive and more commercially oriented than rural cultures; they are most common on the hub worlds of the Arterial Network. Many Sangheili communities fall somewhere between the two extremes of metropolitan and agrarian, for example with a collection of suburban keep estates surrounding a central urban habitat or a collection of small arcology-like habitats comprising a single urban community; these strongly depend on the cultural and architectural traditions in question as well as the requirements of the local environment. Some rural states contain urban centers (e.g. spaceports) but their governing aristocrats prefer to live in countryside estates. Notably, Sangheili urban habitats are built with similar considerations in mind as their traditional keeps, with defensibility being a driving concern in their architecture.

Due to the Covenant's influence, few Sangheili communities are exclusively Sangheili, housing significant populations of other species (often Unggoy, Lekgolo and Yanme'e), largely in a servile capacity and performing duties the Sangheili deem beneath them or outside their purview. Although they often interact with their masters on a daily basis, the dwellings of these species are generally segregated from those of the Sangheili, by necessity in the case of the Unggoy's requirement for a methane atmosphere.

Not all Sangheili inhabit planets; many spend their lives aboard orbital habitats, ships or worldships, endlessly moving back and forth along the slipways of the Holy Ecumene. By far the most notable and populous example of such worldships was the Covenant holy city, High Charity.

Languages
Most Sangheili populations today speak one of the many varieties of Qerenoka, either as a first or second language. Though most of these variants are generally known as "dialects" of the common language, in truth many are distinct enough to qualify as their own languages. Other Sangheili languages that still have many speakers include Brinnu and Zhakhan.

The Sangheili are known for attributing almost painstaking significance to their use of both language and nonverbal communication. Even the little details of everyday interaction are often tacit cultural or political statements, and language is no exception. One of the distinctions where language makes a difference is the axis from Common to High Sangheili - a simplification of the variance in dialects within the Qerenoka language family, now widely known as Sangheili. "Common" Sangheili, often known simply as the Common Speech, is the Covenant's everyday language. Over time, it has become considerably simplified from its roots; a lot of Common Sangheili's more complex grammar (and accompanying expressive power) have fallen by the wayside due to its long history non-native, non-fluent usage, and many alien loanwords have entered the language.

Material culture
The Sangheili have longstanding artisanal traditions, and even with the existence of mass-scale industrial production, craftsmanship is generally held in high regard.

One notable characteristic permeating Sangheili material culture is the relatively abundant use of bilateral symmetry, likely owing to the species' two-thumbed, bilaterally symmetrical hands. This has shaped the ways in which the species designs their equipment, weapons and interfaces (the peculiar shapes of many Covenant weapons being a good example). Scholars have noted that the broader notion of duality and two mirrored sides to all things occurs often even in Sangheili philosophy, though it is debatable whether this is directly related to their anatomy.