Board Thread:Warhammer 40k General Discussion/@comment-88.114.255.138-20130111160957/@comment-3258762-20130408080137

Well, The Emperor didn't defend himself when Horus attacked, and when he saw what Horus had really become, he killed Horus in a blink of an eye. Daemon-Empowered Horus, probably much more powerful then any other Daemon Primarch, dead in a heartbeat.

As for the physical fight: The only way to measure that is the Emperor in his "human" body against Khorne in a "mortal" body. And that's not fair at all, they both do battle in the warp where their power manifests as physical bodies, where I think the Emperor would win either if he used psychic powers or just fought because, as previously mentioned, they are both, at the core, psychic beings.