The Emperor’s Children were the III Legion of the Legiones Astartes – the only one to bear the Emperor’s own name. Their Primarch, Fulgrim, known as the Phoenix, led the Legion with a vision of absolute perfection – in battle, art, and spirit. They hailed from the planet Chemos, where Fulgrim transformed a decaying world into a center of culture and craftsmanship.

At the dawn of the Heresy, the Emperor’s Children were revered as exemplars of the Imperium, but their pursuit of perfection became their downfall. After contact with daemonic powers and the betrayal at Isstvan III, the Legion descended into hedonism, madness, and devotion to Slaanesh. Fulgrim became a Daemon Prince, and the Legion fragmented into warbands obsessed with pleasure and pain.

In the Horus Heresy game system, the Emperor’s Children have access to rules such as Flawless Execution and Perfect Counter, encouraging precise attacks and reactive combat. Their units include Phoenix Terminators, Palatine Blades, Cacophony, and heroes like Lucius the Eternal, Eidolon, and Saul Tarvitz.