Accha on a serious note - I feel that it could be Reem. It would nicely tie up her MLA father also being one of the asurs.
It would also explain how Urvashi (Reem's mother) is always able to guess the right things about Pratha.
I don't think think it's Reem. The red serpent was kept in a laboratory. It was shown in today's episode. On the other hand, Reem was present in Gujral family's party. It's not possible for her to be present in both places at the same time.