Ultramarines

The Ultramarines are the XIII Legion, founded by Roboute Guilliman and considered the exemplars of what it means to be a Space Marine. Their discipline, tactical flexibility, and adherence to the Codex Astartes have made them the most influential Chapter in the Imperium, with more successor Chapters than any other Legion. From their fortress-monastery on Macragge, the Ultramarines defend the realm of Ultramar — five hundred worlds that stand as a beacon of order in a galaxy of chaos. When Guilliman returned during the Indomitus Crusade, the Ultramarines stood at the forefront of humanity's counter-attack, their blue armor a symbol of hope across the Imperium.