User blog comment:IamJakuhoRaikoben/Chapter 405: Tartarus Arc: Part 6 - Magna Carta, Review./@comment-24734283-20141021190952/@comment-7418318-20141021191343

With the patterns on his chest, shoulder and arms, I#d have guessed that this is Acnologia.

Maybe Face really will turn Acno back into a Human and then he's either killed or disappears because back in a Human body, that body can't sustain his age.