Board Thread:Warhammer 40k General Discussion/@comment-6078851-20130130174042/@comment-4264245-20130314224805

They're not loyal even to the Cabal. They want the Emperor to die to make Horus the new lord of the galaxy, but they also want him to be weak enough to have rebellions inside his own side so that the Chaos forces eat themselves and purge Mankind and Chaos Gods. But since they're not on either side, they seem to be gathering strength on their own, keeping the Primarch DNA against the Cabal's wishes.