Cynthia

Cynthia is a mysterious character of this mind. She is a soul that can't control its body, but can awaken as a "reincarnated ghost," tangible enough to fight.

Appearance
Cynthia looks like a partially transparent, blue version of Mack Reapen.

Purpose
Cynthia is Mack's former self, as she was the past body of Mack's soul. Mack, in "A New Friend," learned that she can summon Cynthia when in need.

Combat
Cynthia uses no weapon, but is able to take on the body of Grimm easily, but she can only take the body of humans if their minds process evil doings.