Board Thread:Warhammer 40k General Discussion/@comment-69.142.168.238-20140724005240/@comment-24821739-20140724050529

With all of the Chaos gods behind him, Horus would have killed the emperor. Because the Chaos gods feed off/are the emotional backlash of every known species, it's possible that the Chaos gods knew that the Emperor would not kill his son. The imperial warrior that happened across Horus' path, died horribly. This propted the Emperor to "unmake" horus, as if he was never there. The only reason Horus died was because of this "unknown" imperial warrior.