Persephone

     Persephone, more oftenly called P, is a simple creature. She is an assassin, and a ghost. She has the ability to manifest mostly physically, which lets her effortlessly perform her duties. She actually doesn't get much work anymore, but... hey, she's been around for a long, long time. In fact, it's believed that she's a direct creation of one of the gods, which lets her exist as a ghost with such strange abilities.