User blog comment:CNBA3/Fairy Tail 412 Review/@comment-99.120.149.4-20141208175613/@comment-9595671-20141209070409

Acnologia was a human once, even if he's a dragon now I don't think all of his humanity was able to be erased. The best explanation, which makes sense since he fell after Face's activation, is that Face was able to affect Acnologia because he was a human once.