This guy is neither whm or rdm exclusively. He is a combination of both. IIRC, I have seen him cast Protectra & Shellra (IV I think, but maybe III), Barfira, Hastega, DiaII, BioII, Gravity, Dispel, and tier II nukes. I would not be surprised if one day he tried to bust out some AM or a summon on me... That being said, he's not much harder than any of the other gobs in the area.
He also seems to have no set spawn point, but wanders around the whole area, tending to stay near other gobs and buff them.
I have killed a whole lot of these, but nothing special has dropped, like a Hotrock or anything. The plat. beastcoin could be a possibility though - I feel like they must drop something.