Roboute Guilliman is a prominent character in the Warhammer 40,000 universe, known as the Primarch of the Ultramarines Space Marine Chapter. He was created by the Emperor of Mankind and is recognized for his strategic genius and leadership skills. Guilliman played a crucial role in the Great Crusade, expanding the Imperium of Man and establishing the Codex Astartes, a set of guidelines for Space Marine Chapters. After being mortally wounded in battle, Guilliman was placed in stasis for thousands of years. He was eventually revived during the 40th Millennium to lead humanity against various threats, including the forces of Chaos and the Xenos races. His return marked a significant turning point in the ongoing conflicts of the Imperium.