User blog comment:TheCarrotSaysYumYum/Fairy Tail Chapter 416 (Tartarus Arc - Last Chapter) Review/@comment-4449950-20150119140128/@comment-7418318-20150119153715

I didn't even consider it before now, but maybe Minerva is still a Demon. Maybe this messed up horns and eyepatch appearance is just Minerva's equivalent to the real Demons' Demon Shape and she can go out of it and appear Human, but just didn't feel like it before.

Or maybe Franmalth had something to do with it.