The two concepts I presently have are:
The Vixen - a biological researcher whose breakout occurred during the study of a Fortean animal, a mythological creature called a kitsune. In some strange way, the animal endowed her with its power, and now she is a being of magic with a host of instinctual spells - which she struggles to fit into a scientific view of the universe.
Agent Nathan Dayes - an analyst for the Paranormal Regulation Agency, sorting through reams of data trying to isolate paranormal involvement. He's not sure when his breakout occurred, because his power is to copy the powers of any other superhuman, and he's only encountered them in reports and on video - so initially, he's not sure if he's a paranormal at all.
If asked to choose I would pick Vixen, since Nathan's getting a bit of love in another PbEM.