Horus Heresy Collected Visions

Suddenly, the battering stopped. Through his good eye, the Emperor saw a solitary Custodian had entered the room. Without hesitation, the loyal Custodian charged towards the Warmaster, guardian spear blazing. Horus looked at him and laughed. For a moment he stood triumphant, allowing his bodyguard to see what he had done to his Emperor.

The Emperor instantly realized what was going to happen next, saw the gloating triumph on Horus's face, knew that his loyal servant was about to die. There was no trace of his beloved son left in Horus. Whatever humanity he once possessed had all but been eradicated, now there was only a daemon driven by insane destructive fury.

The Warmaster, turned his burning gaze on the Custodian and his armor was blasted apart. His flesh flaked away to reveal his skeleton then even that was gone, reduced to dust. It was over in moments.