User blog comment:Vivaporius/AT Idea: Imperial Civil War/@comment-3341288-20120409204527/@comment-3398633-20120410203211

Feels right to me. And this isn't the first time the Primarchs had a falling out with the Emperor. Angron? Refused to listen the Emperor, and had to be dragged off of his homeworld. That's clear proof that the primarchs don't have to listen to the Emperor. And Horus?