- #90
There is actually another possibility about what happened. It may not even be the demon slayer magic that is causing this but the fact that Gray touched the Book of END. A book that Igneel stated specifically that only Natsu was supposed to get. It's possible that the part of END contained in that book is so powerful that it can corrupt any human that touches it even if the effect is delayed. So you see there are TWO possibilities in favor of Gray being possessed by some kind of power.
So this means another power up for Gray :D If Gray ends up controlling this power then he has Demon Slayer Magic and a certain power of END.