Lekgolo

The Lekgolo are a species of gestalt organisms and one of the former client species of the Covenant. Individual Lekgolo are small, eel-like creatures. While barely sapient by a conventional definition, these eels can combine together to form sapient "subsistence gestalts" with a networked intelligence and often specific purpose. The cognitive capabilities of these Lekgolo colonies depend on the type and experience of the Lekgolo eels in question, the level of synchrony within the colony, as well as the size of the overall gestalt; the largest Lekgolo "meta-gestalts", which may span entire starships or vast cavern networks, can approach or even surpass artificial intelligences in intellect and processing power, though due to the inherent limitations of biological neural nets, their cognitive speed is generally slower.

The first species to be annexed into the Covenant after the Writ of Union, the Lekgolo fulfilled a diverse variety of roles within the hegemony. Lekgolo gestalts served as heavy infantry, known as Mgalekgolo (or Hunters to the UNSC), though even more of them were drafted for industrial purposes, operating various machinery. Due to the Covenant's strict ban on artificial intelligence and machine learning, specialized, purpose-bred Lekgolo colonies also fulfilled various computational duties from slipspace navigation to probability computation; strains of Lekgolo also served in roles related to deciphering Forerunner relics, such as the inner pathways of the Forerunner Dreadnought.

Anatomy and physiology
The Lekgolo are the Covenant's most truly alien client species; neither their anatomy nor psychology have obvious counterparts in the native biomes of the other species of the known Orion Arm. This foreignness also makes them inherently reclusive; though they do interact with other species as part of their duties within the Covenant, full-fledged Lekgolo communities tend to be fairly isolated, both by choice and as a byproduct of the physical nature of those communities. Due to the Lekgolo's extremophilic nature, they could easily settle worlds unsuitable for habitation by the other Covenant species, with worlds allotted exclusively for Lekgolo settlement being known as "Swarmworlds". As a result of this, the Lekgolo are considered a prime example of the Covenant's classification of an enigmatic species - as opposed to the more congruent species that form the primary castes of the empire.

Mega-gestalts
On the highest level, Lekgolo organize themselves into what are called mega-gestalts or metagestalts. These collectives are enormous, up to thousands of times the size of mobile Lekgolo forms commonly fielded by the Covenant. Many are too large to effectively move or even support themselves in a normal gravity, and as such operate in low-gravity or microgravity environments. In their native habitats, it is such massive colonies that the Lekgolo eventually organize themselves into, burrowing within vast tunnel networks on lifeless moons. Cords of Lekgolo several meters thick link larger processing-nodes which may contain hundreds of discrete parallel-minds existing in a constant state of flux, ever coalescing in and out of mental topologies. Few outsiders have the privilege to witness these tunnel networks, which form vast, alien geometries after centuries of Lekgolo carving - a process dubbed by human xenobiologists as "Lekgoforming".

At this stage, few Lekgolo gestalts literally think alike, as they delight in coming up with new ways to think. Mobile forms such as Megalekgolo or sub-Mgalekgolo are regarded as borderline feral by the standards of these gestalts. However, such fighter-colonies often integrate into larger gestalts at the end of their service, as their unique experience is cherished by the whole. Lekgolo mega-gestalts that particularly value knowledge-sharing and malleable individualities are known as Flux-oriented communions. These are contrasted with Placid tendencies, which are more slow to accept change.

Sometimes, mega-gestalts will spend considerable wealth to obtain a starship. It could be a mothballed carrier or a starliner or a custom bulk freighter. The only requirement is that the ship be large enough to contain the mega-gestalt and all the equipment it can purchase. These starfaring colonies roam the slipspace lanes of the Covenant empire, and sometimes disappear beyond the border regions for decades at a time.

At first, the High Council was loathe to authorize sales to the Lekgolo, fearing that they would seed one colony after another until the entire Orion Arm was dominated by Lekgolo. But, as it turns out, the Lekgolo aren’t as expansionist as the other Covenant species, and rarely set up new colonies.

The Ministries of High Charity were afraid that the mega-gestalts were hunting Forerunner relics, and devoted considerable resources to following and surveilling the colonies’ activity. They discovered that most starfaring colonies do not seek out Forerunner reliquaries. When they do traffic in artefacts, it is only to raise money to repair their ships and their equipment.

For the most part, the starfaring colonies seem to be overly large tourists. They bask in the radio noise of the Covenant’s established worlds, they prowl the debris fields of black holes and newborn stars, and they watch civil wars from afar. If they do have a common goal, it is astronomy. The colonies have deployed millions of probes, and though only a fraction of what they have discovered has been shared with the Covenant at large, it forms the foundation of the Covenant’s knowledge of astronomy and astrophysics.

This gives rise to the third theory, which has yet to be disproven. From the Lekgolo’s perspective, San’Shyuum, Sangheili, Jiralhanae, Kig-Yar, and Unggoy all think alike. So alike that the Lekgolo often call them ‘companion-minds’. Perhaps the mega-gestalts are looking for exotic forms of advanced intelligence similar to themselves. Maybe they’re looking for their own companions.

Psychology and traits
Lekgolo psychology is notoriously abstruse, and does not translate well to the perceptions of Congruent species. Rather than discrete, fixed individualities, Lekgolo consciousnesses are better understood as malleable processes that change shape multiple times throughout the life of a colony. This also means Lekgolo colonies can easily change viewpoints and states of mind as circumstances change. For menial tasks and even fighting, Lekgolo gestalts often effectively turn off their higher mental functions, only to resume them in the next moment. Consequently, a Mgalekgolo can fight fiercely as a feral beast in battle and appear entirely calm a moment later. While morality does not typically concern the Lekgolo in any conventional sense, some colonies do show an interest in it as a mental exercise. Likewise, though the Lekgolo are not naturally predisposed to religion, many have taken a liking to Sangheili war-poetry and philosophy along with the esoteric aspects of the Covenant faith.

Human xenobiologists have called this a "blank-slate psychology" in which Lekgolo collectives adapt their entire mode of thought to the situation at hand.

The four main temperaments
Covenant scholars summarize Mgalekgolo psychology as having four temperaments: Anarchic, Concordant, Meticulous, and Pugnacious.

The Anarchic-Concordant axis determines how cohesive a colony is. An anarchic colony is split into multiple sub-minds, or even individual Lekgolo eels. They do not function as a single mind, but rather as voices shouting in a crowd. This can be a very dangerous state for the colony to be in, as individual members may get displaced or even killed by the rest of the colony. On the other hand, Lekgolo sometimes find the ability to ‘think in parallel’ useful. A common aphorism goes that "It takes a year and a half for a San'Shyuum child to be born, no matter how many women are assigned to the task."

A truly concordant colony is united in thought and purpose, and refers to itself as "I" rather than "We". This may as well be nirvana for the Lekgolo, but maintaining it for a long time is exhausting, as it suppresses the individuality of each individual Lekgolo eel.

Meticulous-Pugnacious also exists on an axis. Meticulous mindsets are contemplative and slow-moving, and barely exist in the moment. They’re too busy predicting the future or contemplating the past. This is the kind of mindset you want for a colony that’s dedicated to processing information or executing long, delicate tasks. On the other hand, such mindsets have trouble adapting to rapidly changing circumstances. There are stories of the UNSC ambushing Covenant excavations, only to be all but completely ignored by the Scarabs and the Locusts until their handlers could wake them from their ongoing process.

Pugnacious mindsets do not plan, they react. Almost the entire colony is dedicated to observing, processing, and reacting. As a side effect, pugnacious mindsets rarely get tunnel vision, but often they blunder into a situation with no thought for the consequences.