Battle Group Endymion

Battle Group Endymion is a UNSC expeditionary rapid response strike group operating since November 2556. It is one of a new generation of small and nimble battle groups designed in response to the changed military-political landscape of the post-Covenant War era, with a focus on a capability to respond to a wide variety of threats with a high speed and efficiency. Equipped with current-generation slipspace drives and Shaw-Fujikawa 'ansible' communicators, expeditionary battle groups such as Endymion are expected to be able to respond to threats within their assigned operational volume in a matter of days if not hours, a vast improvement over the weeks or months such a response would have taken during the Covenant War or the Insurrection.

Comprising the, two frigates and a prowler, the primary focus of Endymion is on speed and maneuverability, both of which are greatly valued in post-war UNSC doctrine. The group is not well equipped for carrying out extended campaigns or large-scale space engagements, but the need for such is rare in the post-war era; typically, rapid response groups such as Endymion are the first significant force to arrive at the site of a crisis, with follow-up actions such as reinforcements being assessed accordingly. Most of Endymion's operations consist of low-key deployments against various pirates and raiders along with the odd escort mission, though the group has partaken in a handful of larger campaigns. Endymion 's sister ship, the Hyperion's Thunder, leads a similar strike group, Battle Group Hyperion.

The Endymion 's pair of frigate escorts are differently optimized for their assigned tasks, as well as a prowler for reconnaissance and support. Additional ships may augment the battle group on specific missions. The frigates, designated Spear 1 and Spear 2, may "ride shotgun" on the Endymion 's exterior hardpoints during sublight cruising acceleration or in slipspace travel, as the Endymion is equipped with the most advanced slipspace drive of the group. Troops can transfer between the ships accordingly (e.g. if Spear 1 is deployed in advance of the rest of the group, which is occasionally the case).

Battle Group Endymion's mission volume mainly encompasses the region known as the Theian Crescent, located within the far southern subvolumes of FLEETCOM Sector 4, with the group's main base of operations being at Neos Atlantis in the Alcides system. The volume is an astropolitically volatile region, intersecting the Orion-side Joint Occupation Zones, a number of abandoned, neutral or lawless systems, a handful of surviving Outer Colonies as well as a growing number of newly-founded colonies in the Hades Gulf, a several-hundred-light-year gap of largely un-colonized space between the hazy borders of the human sphere and what used to be the Covenant Empire. The Hades Gulf is not exactly the only point where the human and Covenant spheres of influence nearly bump into one another; due to the 3-D nature of space and the extent of the Covenant's empire, their territories (depending on the definition) partially surround human space on more than one side. Still, crossing distances of fewer than at least 500 light-years are uncommon, and the Gulf is of significant political, economic and strategic interest as a crossing zone between the two civilizations' territories. The Gulf was originally discovered during the Covenant War based on AI-processed data on outlying Covenant colonies by means of siphoning Covenant data systems, deep-space probes, as well as outlying super-telescopes. At the time, it was flagged as one of two primary viable avenues for retaliatory strikes into Covenant territory (i.e. ones that did not rely on Covenant slipspace transit), which eventually came to pass with the notorious Operation: SUNSPEAR in late 2552. In the post-war years, the region is proving promising as a channel for interaction of a less bellicose nature: in 2556, the Gulfstream Trade Route, formally known as the Pleiades Corridor, was formally opened, connecting the human Outer Colonies in the Theian Crescent and the Covenant's Siakar Expanse. Though essentially a formality (unsanctioned traffic and trade had flowed along the gulf for some time then), the opening of the route held major symbolic repercussions to both sides -- who did their best to ignore the fact the route was set up partly using infrastructure originally established by the Covenant for their invasion fleets.

The name of the Hades Gulf was coined by military strategists during the war. In the post-war era, several less grim names have been suggested for the region, particularly by corporations operating there seeking to make it more attractive for prospective colonists or other corporate interests, though none have truly caught on; perhaps the most neutral and astrographically accurate one would be "Orion Gulf". The corresponding region of ex-Covenant space -- known as the Siakar Expanse -- has since become home to a variety of emerging polities both civilian and military. Some of these post-Covenant factions are eager to expand their interests out to the former "no man's land" and the human colonies beyond, the fringes of the former Covenant having suddenly found themselves in an advantageous position practically bumping into another interstellar polity. This offers many opportunities for trade and even diplomatic alliances, which many autonomy-seeking human colonies as well as corporations near the Gulf have been eager to reciprocate. Meanwhile, warlords operating in the region (including elements of larger groups such as Jul 'Mdama's self-styled Covenant, or more local factions like the Keepers of the One Freedom and the Sons of Heaven) seek to put a dent on the budding atmosphere of hope and prosperity. The trade flowing along the Pleiades Corridor trade route within the Hades Gulf as well as the various new colony worlds and supply stations also continue to attract various raiders, pirates and other delinquents to the region, meaning Battle Group Endymion has their hands full. On some occasions, Endymion's operations even bridge over to ex-Covenant space proper.

As part of the UEG's pact with the Arbiter's Swords of Sanghelios and the larger Concord of allied polities, Endymion occasionally carries out joint operations with members of the Arbiter's coalition -- on some cases the Swords of Sanghelios proper, but more often the SoS' colonial allies, the most common one being a group known as the Chikri-Merkaa Conflux, or simply the Conflux. The Conflux is a post-Covenant alliance based out in the far reaches of their colonial empire, and is one of several SoS subgroups that the UNSC often interacts with. Military strategists initially had difficulty conceptualizing the scale and scope of the former Covenant's colonial empire. While still under active investigation, ONI estimations speak of thousands of developed systems and at least an equal number of various outposts or unrecorded settlements; the Covenant's influence spans the entire breadth of the spiral arm and much of its length -- a humbling concept from a human standpoint, as humanity is only now getting used to crossing distances of more than dozens of LYs. Tracing Sangheili and Kig-Yar colonial growth in particular has proven difficult even to the Swords themselves due to the species' preference for distributed governing systems, the stochastic interplay of their hundreds of independent colonial growth vectors, as well as the age of their starfaring civilization(s).

A common misconception is that the Swords of Sanghelios are culturally, aesthetically or governmentally monolithic; rather, what are known as the "Swords" in common discourse is in fact a large (and at times loose) coalition of numerous polities known formally as the Concord. More specifically, while the Swords of Sanghelios proper are the military government of Sanghelios and the Urs system, they are themselves part of the core alliance known as the Crimson League, consisting of several dozen major core colonies (most of them founded pre-Covenant). They also maintain a large number of alliances to dozens of lesser interstellar polities further out across ex-Covenant space, known as the Outer Vigil. These colonial factions do not always subscribe to the letter of the SoS' doctrine and frequently maintain their own names, cultures, and aesthetic preferences, but are by and large allies to the greater coalition of those sympathetic to Vadam.

The Chikri-Merkaa Conflux, often referred to simply as the Conflux, is one such polity. A natural post-war outgrowth of an already existing trade alliance between Kig-Yar and Sangheili clans in the region of space known as the Chikri-Merkaa Strand in the former Covenant domain of the Siakar Expanse, the Conflux is a small player in the grand scheme of things, but they do seek to expand their influence in their home region of space. On a general policy level, their differences to the Swords of Sanghelios proper are mostly cultural and aesthetic in nature, with only minor policy differences; all the Arbiter is concerned about, however, are common allies and enemies. Groups such as the Conflux do not necessarily contribute much to the war in the Sangheili core worlds, but they do serve the Arbiter's interests across the ex-Covenant colonies, something that is particularly valuable near the expansion spheres of humanity or the various Covenant Fringe species. Primarily a civilian government, the Conflux maintains a small but well-trained and -equipped military, designed for speed and flexibility -- which makes them ideal partners for Endymion's mission -- at least as 'ideal' as a post-Covenant group can be.

Fleet elements

 * (CA-771), . Battle group command vessel. Constructed at Neos Atlantis' Tethys Shipyards and commissioned in 2556. Maintains a flight of Longswords as well as a Broadsword squadron along with various support and auxiliary sub-vessels.
 * (FFG-417) / Spear 1, . Tip of the spear; specializes in fast attack and space combat. Maintains only a nominal troop complement by default, though forces can be transferred aboard if need be. The Fourth Horseman is the second frigate to be hold the title of Spear 1, following the loss of the original (UNSC Elan Light) in mid-2557.
 * (FFG-223) / Spear 2, Charon-class light frigate [midlife-refit for current-gen specs]. Primary troop landing ship and secondary escort combatant vessel. In time, Ahab may be replaced by a new type of warship along with other aging spaceframes, though until then midlife upgrades can extend their viable frontline operational life for at least ten to twenty years, barring major technological leaps.
 * (PRO-49811), . Reconnaissance and electronic warfare support craft.

Troop complement
Overall, Battle Group Endymion's troop contingents are designed for speed and mobility, and tend toward specialization.
 * 191st Battalion, UNSC Marine Corps
 * NAVSPECWAR Group ONE -- Expeditionary Force Theta
 * 71st Shock Troops Battalion
 * Fireteam HALBERD (SPARTAN-III)
 * Headhunter Team DAGGER (SPARTAN-III)
 * Naval Special Warfare Strike Teams (3)

ONI
Endymion maintains a small handful of ONI liaisons, in addition to the crew of the With Subtlety and Nuance, who are, as Prowler Corps personnel, formally under Section II's payroll albeit heavily integrated with Battle Group Endymion's conventional Fleet chain of command.

Endymion Science
While primarily a military operation, Endymion maintains a small scientific complement with various xenosciences specialists for unexpected findings requiring immediate attention. Endymion additionally houses the "science pod" UNSC Clarke Was Right (AGR-784), a. Possessing no slipspace capability, the class was essentially built on the spaceframes of refitted for research purposes after the Hadrian-class was replaced in mainline service. Aside from ferrying science personnel and equipment to groundside research sites, the Clarke Was Right is primarily used to conduct research into potentially dangerous Forerunner artifacts or other hazardous materials off-ship without endangering the core battle group, let alone the flagship. When the Clarke houses Forerunner artifacts, it always maintains an exclusion zone preferably in excess of a light-second to the main vessels of the battle group and uses ultra-secure point-to-point communication protocols, with the hazardous materials themselves handled in sealed Faraday enclosures. However, in situ research on the ground with all the appropriate countermeasures is preferred whenever it is feasible, as allowing Forerunner technology to come into contact with a UNSC vessel in the first place is deemed highly risky.

Transient/non-official elements
During joint operations, Battle Group Endymion is frequently supported by vessels from the Chikri-Merkaa Conflux, typically light capital ships such as corvettes, frigates or destroyers. On some occasions where mission parameters have demanded especially close cooperation, Endymion has maintained an embarked Conflux combat team, drawn from volunteers in the alien alliance's special force group known as the Foremost Legion. While the team's presence is above all a diplomatic gesture to better acclimatize the two sides to cooperation, initial results in unit integration and joint operations have shown promise, though doctrinal differences and misunderstandings continue to cause confusion.