@MadParadox
I'm sure that (s)he will stay in this form. Because the demonic madness was only the side effect of this transformation (a so-called engulfment of demonic flame). And I suppose the dragon will cure this effect. Dark has allready reached the Master-class, and there is no way back.
@Genoshock
It looks to me like he's forgotten where he is now and he is fighting with them like they are an enemies from the West and this battle is happening in Murim. Some kind of madness.
The warning for girls: Beware of getting your first period during the meditation on the top of the weired magic tower wearing the powerfull artefact on your finger while using the demonic spells.