The Legio Apocalypsis is a Loyalist Titan Legion of the Collegia Titanica, one of the military arms of the Adeptus Mechanicus. Scant records and estimations suggest it was founded late in the Great Crusade. Its total current strength stands at approximately 80 Titans.
Its homeworld is the Forgeworld of Layria in the Astoth Sub-sector located in the Ultima Segmentum. The Legio has a vast history of warfare spanning across the galaxy during the Great Crusade up to the present day, where they have fought alongside all manner of loyalist forces against every conceivable foe that threatens the Imperium. Due to their close proximity and shared combat history with the Tempest Angels, the Legio Apocalypsis maintains a strong friendship with the Chapter, accounting for over 90 percent of the battles in which the Astartes Chapter has fought alongside Titans.