User blog comment:Omega natsu2/Chapter 387: Tartarus Arc, Part 4: Father and Son, Predictions./@comment-24784846-20140530224650/@comment-5233713-20140530230342

I like your theory of Deliora being summoned by Gray and Silver being angry at him for that, but for Silver's transformation, I think he just went up against them using his Devil Slaying magic, he lost and was turned into a demon like Minerva was.

After all Mard said he could actually promote someone to a 9 demon gate. That would actually be a good story, it stll is a hell of an odd that they both ended up learning Ice magic, but I could learn to live with it.