[Well ghost with or without wings isn't wrong. That was basically his state when he was unexpected discorporated. But, back in the oldest of times, at their very nature.]

It's difficult to describe. It's more... conceptual.

[Form. Is a funny thing for beings that don't necessarily have to take form. That can be smaller than subatomic particles or well, frighteningly large at whim.]

Remaining human shaped, generally, it's probably a good change. There's something to be said for form and its effect on the overall being.