User blog comment:Abyssal Horror/Horus Heresy AT/@comment-9465750-20120720085204

how about:

Horus in the end facing Valdor and then the Emperor. Horus would kill Valdor, but would be quite hurt. Then the Emperor comes and the two fight. Seeing that the Emperor would win, Horus orderes all his men to fire on the Vengeful Spirit, thus the Emperor still needing to get on the Golden Throne and yet, Horus wouldn˙t be fully destroied, only killed. The traitors retreat. Then, Horus could be revived by the Gods, even more poweful, to then lead the Black Crusades on the IoM. The surviving loyal primarchs: Lorgar, Perturabo, Night Hunter, Omegon, Magnus and Mortarion would form the High Lords of Terra ... first and only. (Vulkan would go missing, Angron and Fulgrim killed)