[quote=Derpestein]
Oh no, I'm just saying that it looks like he'll turn into a wraith, cause from Madoka Magica, Despair = Transformation.
[/quote]

Wasn't the whole point behind Madoka becoming Godoka to prevent this happening? Magi who go over the edge no longer turn into Witches but just disappear, as you see in the anime. Wraiths are a different entity altogether.
Admittedly, I haven't had the time to watch Rebellion yet but unless Urobutcher radically altered the story I can't see that mechanic changing.