Watcher Keep - Service of Demetrian Titus: Following the Liberation of Graia, Captain Demetrian Titus, commander of the Ultramarines' 2nd Company, had been imprisoned by Inquisitor Thrax on suspicion of heresy for his unaccountable failure to be affected by Warp sorcery during that campaign. After a standard century of captivity by the Inquisition, Thrax led an operation against the traitorous Grey Slayers Chapter, who had become corrupted by the insidious machinations of the Dark Gods. Leading a large retinue of Grey Knights upon the corrupted Chapter's homeworld, they began to purge the Heretic Astartes in earnest.However, during the conflict, Thrax was possessed by a Daemon, and in turn, was killed by his retinue of Grey Knights. In the wake of Thrax's death, forces drawn from the Red Hunters Chapter were dispatched to investigate and secure the Inquisitor's holdings. In a remote Inquisitorial watch station far to the galactic south, a Red Hunters kill-team discovered almost a score of Space Marine interrogation subjects locked in stasis cells, preserved from the passage of time. Titus' story could have come to an end there, had the Inquisitor responsible for overseeing the seizure of Thrax's materials felt inclined to conceal the shame of her fellow Inquisitor. Instead, Titus, and several other warriors of various Chapters who had attracted Thrax's attention, were conveyed to the Deathwatch watch fortress of Watcher Keep to be evaluated.After being found free of Chaos taint or disloyalty, Titus would eventually enter the service of Watcher Keep as a Deathwatch Black Shield, his former identity unknown to those he fought alongside. Having received no word from his brethren since his incarceration, he came to believe he had somehow brought shame upon his name and that of his beloved Ultramarines and determined that he was not worthy to bear the Chapter's name. Overcome with shock and grief at his discommendation, Titus had all of his former Chapter's heraldry purged from his battle-plate and assumed a self-imposed exile as an outcast Black Shield.If he could serve the Imperium and his Emperor as an alien-hunting battle-brother of the Deathwatch until death claimed him, he would do so gladly, having no more desire for personal glory than he did at the start of his life as a Space Marine. Assuming the name "Nullus," Titus honourably served alongside his fellow battle-brothers in the Deathwatch for many standard years. During this point in time, unbeknownst to Titus, the Ultramarines' primarch Roboute Guilliman had been resurrected on Macragge during the Ultramar Campaign of the 13th Black Crusade, and now once again served as lord commander of the Imperium and Imperial Regent.Guilliman led his newly declared Indomitus Crusade against the various enemies of Humanity, as the galaxy had literally been split in two by the opening of the Great Rift at the start of the Era Indomitus, a galaxy-spanning Warp rift formed in the wake of the destruction of the Fortress World of Cadia at the hands of the Warmaster of Chaos, Abaddon the Despoiler. However, this crusade left many worlds weakened after committing large numbers of troops to the war effort, leaving them more vulnerable to invasion.During this time, the Fourth Tyrannic War began in the Segmentum Pacificus, as swarms of Tyranids, ravenous extragalactic aliens that threatened to consume all life in the Milky Way, invaded the already-beleaguered strongholds of Humanity in the galactic west.Titus, as "Nullus," deployed as part of the Deathwatch's Kill-team Kasaeran, deploying to the Recidious System via Corvus Blackstar. During their mission to the Recidious System, Nullus and his squad were tasked with reinforcing the Astra Militarum forces based there on the world of Kadaku, who were already weakened by the toll taken by the Indomitus Crusade muster across the Imperium Sanctus.The kill-team's gunship was brought down by swarming flocks of winged Tyranid bioforms, forcing the warriors to engage with the insectoid aliens on the planet's surface. Here, Titus was gravely wounded by a monstrous Tyranid Carnifex. As life bled from his torn body, his Deathwatch battle-brothers lying slain around him, he prepared to commend his soul to the Emperor. It was then that Titus was reunited with the warriors of Ultramar, as an Ultramarines strike force arrived to relieve the Deathwatch at Kadaku.Varro Tigurius, Chief Librarian of the Ultramarines, detected the soul-sign of the warrior once known as Demetrian Titus in the local Immaterium as their strike craft traversed the Warp. Even as the Tyranids' Shadow in the Warp began to cloud Tigurious' witch-sight like cataracts, the Chief Librarian recognised he who had once been the captain of the Ultramarines 2nd Company.As fate would have it, Tigurius travelled aboard the Righteous Fury, the same vessel that had borne Titus and Trajan before him to battle many times, and it was this mighty voidcraft of the Chapter that broke from the Warp at the edge of the Recidious System. There, the strike cruiser prepared its Thunderhawk gunships to deploy to the planet where the broken form of the Black Shield known to his comrades as Nullus lay dying.The Ultramarines 1st Company arrived on the planet to reinforce the Deathwatch forces, bringing none other than First Captain Severus Agemman and Chief Librarian Tigurius. The Ultramarines fought valiantly, their weapon blasts wreaking devastation upon the Tyranid bioforms with the carefully born discipline of experienced Tyranid hunters, holding back the tide. They arrived too late to save Kadaku from falling to the Great Devourer but the Deathwatch warriors of Watcher Keep were able to recover their dead and wounded and fall back into the Ultramarines' gunships. All except the ravaged Black Shield Nullus, who Tigurius ordered returned to the Apothecarion bays aboard the Righteous Fury.Titus' wounds were grave, and it was decreed that he would undergo the "Calgarian Rites," the Ultramarines' name for the Rubicon Primaris, in order to have even a chance of surviving. Titus withstood the procedures necessary to become a Primaris Space Marine as stoically as he had endured any of Inquisitor Thrax's interrogations and was remade stronger than he had ever been. When he awoke, he was surprised to find himself honoured with the rank of lieutenant under the command of Captain Sevastus Acheran of the 2nd Company -- a warrior who had only recently left the Scout Marine reserve when Titus was taken from the Ultramarines alm,ost a standard century before. Once more Titus resolved to do as was bid of him by his Chapter, and serve under a warrior who held the titles he had once held.There were those amongst the Ultramarines who were apprehensive about Titus' return to the Chapter. Chief Librarian Tigurius, however, had performed his own examination of the former captain and found him to harbour no taint, before psychically communing with Chapter Master Marneus Calgar who authorised Titus' immediate reinstatement. Their word was as adamantine, and Titus was officially welcomed back into the warrior brotherhood of his gene-sire. Lieutenant Demetrian Titus, once and once more of the Ultramarines 2nd Company, would bring the wrath of his Chapter to the foes of the Imperium anew.