User blog comment:CNBA3/Dragon King Festival and E.N.D/@comment-7418318-20140501093123/@comment-4829046-20140501094154

Obviously. Zeref decided to eradicate humans. So wouldn't make sense for him to be on their side.

Technically Endless did take up a form, though mostly for appearance sake and it did have a pseudo-consciousness through Mother Darkbring. I know your point though that it wasn't really a "person" in the traditional sense but laws of immortal entities still applies to say that Endless had consciousness, or else it wouldn't be able to do all that manipulating.