>After the Emperor felt the true extent of Horus' power as He rushed to face him aboard the Vengeful Spirit in the final stages of the Siege of Terra, He realized that victory would be unlikely unless He empowered Himself greatly. Out of desperation, the Emperor drank from the Warp but on a scale previously unseen. Taking the form of a lightning-sheathed sphere of obsidian, the Emperor's power was such that He even unintentionally slew all of the Custodians around Him, turning them into little more than heavily burnt walking corpses. The Emperor proceeded to sweep across the madness of the Inevitable City, causing Daemons, the Lost and the Damned and even Traitor Space Marines to flee in panic before Him.[1c]
>By now, the Emperor was ascending into a full Chaos God, though He believed the action was necessary in order to kill Horus and save humanity. Malcador was distressed at sensing what his friend had become, believing He had gone too far.[1d] However it was then that the Emperor was confronted by Ollanius Persson, John Grammaticus, Leetu, and Garviel Loken. Persson confronted his own friend, talking him down from the abyss of corruption by reminding Him of His humanity. Shocked that He had encountered Persson for the first time in millennia at this specific place at this specific time, Persson convinced the Emperor to have faith and give up the power He had built up even if it meant gambling humanity's future in a battle He was likely not to win. This ultimately convinced the Emperor to shed the mantle of the evolving Dark King, causing a blast of power to sweep across both Terra and the Vengeful Spirit that banished much of the Warp-madness spread by the traitors.[1d]