- "We are the sons of the Emperor. We are the angels of death. We are the Emperor's Mercy. We are the Emperor's Wrath. We are War."
- — Tome of the Skull, Third Psalm.
The Skull Templars are a 13th Founding Chapter of the Adeptus Astartes. Their origins are shrouded in mystery and rumor, but this is to be expected of a Dark Founding Chapter. While their earliest records are known only to the Inquisition and to the Chapter itself, they have gained a reputation among many Imperial Agencies as devout worshipers of the Emperor and skilled swordsmen, never lacking in faith or fury.
The Skull Templars preside over King's Reach, a feudal world on the edge of Segmentum Ultima, near the border with Segmentum Solar. The planet's moon, Concordance, possesses an inactive portal to the Warp from the Dark Age of Technology, presumably used to experiment with travel between worlds. The old facility used to house the portal was rebuilt and expanded into the Skull Templars Fortress Monastery. From this fortress, known as Templar's Keep, the Skull Templars guard the Portal, keeping it safe from aliens, heretics, and daemons, until the day when it can be safely dismantled or utilized for the benefit of mankind.
As of 999.M41, the Skull Templars have evacuated all of King's Reach for the first time in history as the Fourth Siege of King's Reach has begun, this time with a two-pronged attack from the Orks of Waaagh! Snotlah and the chaos marines of the Thanes of Hell, who have come to find the Warp Portal and open it for a much larger chaotic invasion. Alongside the Skull Templars stands the Hunters Errant, Battlefleet Rexus, and the Maccabian Janissaries, each just as ready to sacrifice themselves to keep the portal out of the enemy's hands.
The Skull Templars first appeared in official Imperial records in 600.M36 when a squad of Terminators bearing the signature skull and longsword emblem engaged the Brides of the Emperor in the Terran Crusade. These marines, identified as Skull Templars, were loaned to the Imperial Fists for reasons unknown. They were ultimately slain to the last, but they had managed to keep at least two important routes to the Ecclesiarchal Palace open for the Adeptus Mechanicus and the gathered Astartes forces. These ten heroes were returned to their homeworld of King's Reach, where they were given their last rites and laid to rest upon a great funeral pyre. Their names became legend: Remont, Hugon, Artur, Waltmund, Hamon, Petyr, Gyffard, Isembart, Quinhelm, and Hamelen.
The Skull Templars were given dominion over King's Reach at some unknown date, most likely to keep watch over a particular dangerous piece of archeotech called a dimensional gate, which was discovered upon the planet's moon, Concordance. The dimensional gates were an experiment from the late Dark Age of Technology that aimed at opening a portal to another universe, but instead created new gateways for daemons to enter the materium. Most of these gates were either destroyed or led to the creation of a daemon world, but the discovery of an intact and inactive one suddenly presented the possibility for a new threat: if King's Reach were to fall to any forces of chaos, then the dark gods would have a staging point in the materium for a massive invasion of Segmentum Solar, with a warp portal for daemons to enter through and a daemon world to maintain them. Such a scenario was utterly terrifying, so a new space marine chapter was most likely founded to keep watch over the dimensional gate, safeguarding it from the champions of chaos.
The Burning of Lyara, 744.M36
Lyara was, by all accounts, a truly beautiful world. Its trees were feathered with violet leaves, and its oceans were azure as sapphire. Certainly this planet should've been ripe for the taking, but there was only one issue: a xenos species, called the Lyarans, were already living there, and they were just beginning to experiment with Warp travel. Attempting to attack them with the Astra Militarum was impractical due to the many civil wars taking place at this time in order to purge Goge Vandire's remaining supporters. So the Skull Templars, at full strength and ready for battle once more, were sent to wipe out the Lyarans.
Four full grand companies attacked the moment they acheived orbit with Lyara. The Lyarans were ill-equipped to face the space marine ships, so the Skull Templars almost immediately achieved air superiority. With this phase achieved, half of their forces made planetfall and set out to destroy the Lyaran civilization, burning cities annd toppling monuments as they marched on.
Lyaran heavy weapons proved to be abundant and deadly, but this was hardly an issue for the marines, who returned with land raiders and even a few fellblades. In the end, one hundred marines had fallen in battle, but such losses were negligible to the outright slaughter of the xenos.
After Lyara was thoroughly scoured and most of its cities were laid to ruin, the Strike Cruiser Benevolence Lost turned its attention to the planet's twin moons, Yanis and Vigen. The Lyarans living here had hoped that the invaders would overlook these refuges. They were wrong.
The Benevolence Lost disgorged several Thunderhawks, each bound for the colonies on Yanis and Vigen. None of the space marine vessels were destroyed due to the apparent lack of defenses on the moons. The Templars, each with a terminator squad on each moon, quickly tore through the security staff and slaughtered the remaining Lyarans. When they had search through every crevice they could find and determined that there were no more of their adversaries, they had ceased and returned to the Thunderhawks.
With the xenocide of the Lyarans complete, the Skull Templars returned to King's Reach and allowed mass conveyors to bring new human colonists to Lyara. Unknown to them, some Lyarans had survived in another system, made aware of the destruction of their race by the agents of Chaos.