Ancient undead spirits of the Haven, it seems as though something within the dimension is holding its spirit in a living state.
It's uncertain whether the creature originally had wings prior to its death, or that it obtained them when returning as a spirit, but it does seem to use them quite heavily.

Angelicas have a dangerous tendency to target unsuspecting travellers and steal them away to the heavens.
Upon spotting a potential victim, it will glide towards them and apply an uncontrollable levitation effect, rising up with its target until its death or falling demise.