Aulus Caelius

Aulus Caelius is an infamous Brother-Initiate of the Ordinators Chapter of the Adeptus Astartes. He was seconded to Deathwatch and the Ordo Xenos as a penitentiary sentence for his costly failure in a battle against a raiding fleet led by the Dark Eldar Kabal of the Screaming Heart in a raid on an Imperial Chartist Convoy carrying pilgrims to the Azuran Sector world of Tharan V while fleeing unrest in the Southwestern Segmentum Pacificus that was deemed to have resulted in the death of his Inmintanii (Sternguard) Squad, 6 other Ordinators, over 400 serf crew, and nearly 60,000 Imperial pilgrims and voidsmen.

History
Aulus was born to a peasant family on the Knightworld of Tharan V in the early 8th century M41. Recruited by the Ordinators in the annual Tournament of the Aspirants on the world, he quickly proved himself highly adept with both the bolter and combat blade. In discovering this natural skill - greater than most in the chapter - he also developed arrogance and a love of bloodshed. Punished for it severely as he progressed in the three decade long Neophyte stint of service required of each Ordinator aspirant, he was eventually forced to see his failings and overcome them in the brutal and secretive Rite of Purification in which he was forced to overcome a Bloodletter of Khorne in spirit and willpower.

Though this did not abolish his capacity to make these same mistakes, he began to develop an intimate understanding of the mind of those that served Chaos. In his years since his initiation into the line companies and true brotherhood of the Cult of Ordination, he has developed a sense of humility, introversion, and proclivity for brutally critical introspection that often comes off as brooding to outsiders, earning his nickname by other brothers of the chapter. Despite this, when faced with battle, he has proven to be an able and even charismatic (if only by virtue of his bravery and concern for his brethren) leader, imbued with a sense of tactical acumen and armed with great personal skill in battle.

Though he has fought in some of the most brutal combat of the chapter against Chaos and Xenos alike, it was his failure to anticipate the workings of the Dark Eldar mind that allowed him to fall for a trap in leading a squadron of Gladius-class frigates and Hunter-class destroyers against a roughly equally sized Dark Eldar raiding fleet that attacked a pilgrim convoy emerging from a Mandeville Point in the Valdorus Subsector en route to refuge at his birthworld. Tricked by the then-Dracon Jizai Hellsun, he boarded a ship attempting to kill the Dracon only to find a group of Incubi and Blaster-armed Kabalite Trueborn on the bridge as the Dracon snuck onto his own flagship and those of the convoy using Impaler Assault Boats to seize slaves. The ambush was brutal, and, with the aid of Hellfire Bolter rounds and his Powerfist, he emerged as the only survivor of the raid. Dragging the bodies of his fallen squad back to their Caestus Assault Ram, he retreated back to his ship without enough time to mount an effectual defense of the fleet. His serf First Officer in command of the ship and his fellow Astartes ship commanders were slain by raiding parties and the force left leaderless.

As the raiding party departed as quickly as it arrived, Caelius realized a bitter truth. His failure to truly understand his enemy had led to the deaths of countless of innocent humans and far too many of his brother Ordinators and their faithful serf crewmen. Upon returning to Arx Numinex, First Captain Marius Ferox summarily sentenced him to a century of service to the Deathwatch as a form of exile and lesson in understanding what he had failed to study before - the mind of the Xeno. His hatred for them has only grown since. His determination to never fail his brothers around him has grown even more.