Overview of Legiones Astartes II
The Bale Hounds legion, originally designated the Astral Wardens, are the IInd Space Marine Legion created by the Emperor of Mankind, and have always acted as stalwart, yet caring, defenders of Imperial citizens. The legion was noted, even during its earliest days, for having the second highest number of psychically gifted Astartes, roughly 10-20% more than the Blood Angels, but nowhere near the numbers of the XVth Legion, now accursed traitors. Despite this, the Legion's geneseed was noted for being incredibly stable, almost comparable to both the Ist and XIIIth legions' geneseed.
Their Primarch, Arwyn Clay, was found on a planet designated as Arcadia Prime, within a sector that rests in the borders between the Segmentums of Obscurus and Ultima, a resource rich but feudal world. According to what few records have been provided, Arcadia Prime, or simply Arcadia as the locals call it, suffered from the cruelty of insane psyckers who declared themselves the Sorcerer Kings, who worshiped or aligned themselves with a group known as the fomori, which many realized were the Ruinous Ones. The Primarch was raised by a couple who were a part of an order known as the Wild Hunt, a militant group that resisted the Sorcerer Kings, and were led by a council of elders. Arwyn was trained to harness his psychic potential and became a powerful psycker, or derwydd a local term of respected shamans and teachers, later he would lead a crusade to fully liberate Arcadia from both the Sorcerer Kings and Ruinous powers.
The Primarch destroyed these cruel dark kingdoms, and replaced them with an ancient clan society, yet Arwyn never proclaimed himself a ruler. Indeed as far as the clans of Arcadia were aware he only commanded the elements of the Wild Hunt, however he was considered the planet's High Derwyyd, and every clan chieftain would never turn away his council. It is difficult to tell which tales of the Primarch's actions during this time are exaggerations, fictional lessons, or the honest truth, all except for a tale known translated to gothic as Sealing of the Highland's Hellmouth and Landing of Sunblessed Lord. This tale tells of Arwyn leading his forces to destroy a warp gate, being guarded by forces of the great enemy, and fighting to a stalemate until the Emperor landed and aided him.
It is said that upon meeting the Emperor, Arwyn welcomed him with open arms before joining the Imperium of Man, with the promise that Arcadia would never be governed by one who was not born under its sky. After spending a year of tutelage under Malcador the Hero's guidance upon Terra, Arwny would join with the first one thousand warriors of his legion on the newly forged Legion flagship, Arcadia Retribution. Like most of the Primarchs, Arwyn reshaped the legion to fit his ideals of war, but also subtly taught them doctrines that would shield their minds from the touch of Chaos. The first war led by the Primarch was persecuted against another lost tribe of humanity that failed to invade Arcadia in hopes of taking its clansmen as slaves, in response the Primarch led the his warriors to an overwhelming victory, and renamed the legion as the Bale Hounds, or Cu Sith Arcadia.
Throughout the Great Crusade, many Imperial commanders noted how easily accommodating the Bale Hounds were in formulating battle plans, and became famous for their mantra of Adapt and Overcome. As such, the Bale Hounds never conformed to any single method of war, using anything that their commanders believed would see them earn a victory, yet their warriors are extremely disciplined. Where the Space Wolves fight alone and answer to none but the Emperor, the Bale Hounds will fight alongside their allies, and heed their council in all theaters of war. Much like the XVIIIth Legion, the Salamanders, they prioritize safeguarding the lives of civilians, and much like the Thousand Sons coveted knowledge as they knew it would serve them well in the future.
There is cause to believe that even during campaigns fought alongside other Legions, that the Bale Hounds persecuted war against the ruinous powers to reclaim the populace and their worlds. It is said that the reason for the Rangdan Xenocide's long and costly duration, was because the Primarch was hunting and banishing daemons that had breached reality. Even with access to the Legion's own records on that dark war, there is very little that details the Primarch's activities during the war. This secrecy is likely what earned both the Emperor and Malcador's trust to tackle the most tainted worlds, and purifying them to be suitable for the Imperium of Man.
There are records that indicate that when the Emperor named Horus to be the Warmaster for the Great Crusade, that Arwyn was amongst those who supported Horus' elevation to such a position, believing that he had the most experience of all Primarchs. Unfortunately, the legion's forces would be allocated to the farthest fringes of the galaxy during the events that would lead up to the Horus Heresy, and after Horus' fall to chaos was increasingly sent to more difficult theaters away from the Warmaster's forces. After being frequently denied the chance to speak with his brother, Arwyn gave a small fleet to the warriors of the 1st Host to sail for Terra and speak with Malcador or the Emperor about Horus' recent strange behavior. This coincided around the time Horus and his fellow rebels first declared their secession from the Imperium, and the war they would wage against the Emperor.
After the news of the atrocity of Istavaan III, Arwyn pulled back his forces to sail for the Istavann system, but were delayed by sudden Warpstorms, which delayed his arrival until after events of Istavaan V. Luckily the Primarch coordinated with a reinforcement fleet of Raven Guard to break the blockade, and rescue the survivors of the betrayal. After learning the full extent of the betrayal from Corvus Corax, Arwyn sent his legion's 3rd Host supported by a small fleet to protect Arcadia. With Arcadia Retribution acting as the flagship for his hunt of the traitors, he welcomed any of the Iron Hands and Salamanders to join him in avenging their Primarchs. Those who volunteered he welcomed and they began their hunt for the traitors.
Many of those battles remain undocumented simply due to sheer intensity and speed in which the Bale Hounds persecuted their hunt of the traitors. However, a chapter of the Word Bearers attempted to invade Arcadia, yet they were swiftly crushed by the 3rd Host and the system defenders. There are whispers that the 3rd was supported by Craftworld Eldar, but thus far my own investigations have borne no evidence to support this claim. Meanwhile, many of the legion's other recruitment worlds were raided by traitor forces for supplies and often left them corrupted shells of their former selves.
Impressively, despite the Bale Hounds honoring the edicts of Nikaea, the legion rejected the Chaplain specialist role, instead entrusting the upholding of the Imperial Truth to his former Librarians. Doubly impressive is that it was the words of both the Primarch and a Terran Librarian who convinced the council to see the continued benefit of deploying approved psychic disciplines, yet the Emperor still forbade the use of combat psyckers. However, many throne loyal commanders have freely admitted that had it not been for the Bale Hounds' mastery of psychic disciplines that many worlds and vital holdings would have been lost to the arch traitors madness.
While every legion of his majesty's Space Marines are seen as the greatest experts in certain fields of war, only a few can claim that they are self-sustaining forces, such as the Ultramarines, Iron Hands, Salamanders, and even the Bale Hounds. Recently it has come to light that the Hounds have committed not only their tech-marines to further understanding of the lost sciences of STC templates, but allowing many of the legion's Forge Masters to experiment and reverse engineer alien technology. The Legion also has a higher percentage of retrieved geneseed, and greater number of trained apothecaries.