An imposing and cold man with a severely scarred face[1c], at the time of the Thirteenth Black Crusade Trajann was considered to be perhaps the deadliest individual warrior in the entire Imperium. Those who know of Valoris' existence, speak of him with reverence and considered the Captain-General to be a representative of the Emperor. Originally an Allarus Custodian he has ran two successful Blood Games, a record that remains unbroken. While serving as an Allarus Custodian Trajann gained famed in the destruction of the Space Hulk Mournful Siren, the defeat of the Genestealer Cult of the Emperor's Writhing Shadow, and spearheading a preemptive strike against Waaagh! Krushfist. After these feats he was accepted into the Companions for 22 years before he was reassigned due to his desire to be more proactive. Thereafter he gained the rank of Shield-Captain and spent several centuries leading sorties throughout the Sol System and beyond. He was elevated to the position of Captain-General following the death of Andros Launceddre during the Years of Madness. His rise has seen the Custodes become the most proactive they have been since the Age of Apostasy.
Though the Captain-General traditionally only served as one of the High Lords of Terra under the most dire of circumstances, as during the War of the Beast, the fervent persistence of Chancellor Lev Tieron persuaded Valoris to take the seat left open by Lord Brach. Tieron had hoped that Valoris would serve as the High Lords' deciding vote to abolish the Lex Imperialis, which would allow the Custodes to leave Terra and fight against the Despoiler's forces[1a], but the Captain-General disagreed with this. He was about to vote no against the abolishment and defeat the measure when pandemonium broke out as word of Cadia's destruction reached the High Lords' chambers.[1b]
During the subsequent Second Battle of Terra against the forces of Khorne, Valoris was the overall commander of Imperial forces at the Imperial Palace and personally led a charge of 4,000 Custodes from the Lion's Gate. When Roboute Guilliman arrived from Luna Valoris cooperated with the Primarch, much to the disdain of several High Lords like Irthu Haemotalion. Valoris even allowed Guilliman to stand before the Golden Throne itself.[1d]