Shade
Monster Junkie
I am OK keeping the treasure constant, or we could just not have it gather treasure - maybe it's only interested in being Fiendish?
Good point. It would probably only be interested in items to use to hurt mortals, which would just complicate its stat blocks. Where does its 20 HD treasure go in the summertime?
My vote is now for "none".
So +1 frost / +2 frost seeking / +3 icy burst seeking? No objection to that.
Considering its other powers vary by season I'd prefer its bow do so as well.
Let's await freyar's take, but I'm cool (pun intended) with that.