Phase-4 is one of the many clones of Kasumi in the Dead or Alive series. She's the only one that seems to have a conscious, though, and she doesn't like fighting/killing, as much as she's forced into doing it. That's the gist of her backstory... since she's only ever been a DLC characters she doesn't have much of a background.

Most of the body's just a black Boss Fight female blank, with some painting (mostly the head/hands, but also the stripes you can see on her limbs when she moves. The heels come from a Zombie Lab Keanna. I hope they make like some boss fight compatible heels as accessories/on blanks because Zombie Lab are expensive! Cloak is a deliberately tattered and ripped one from Emperor Palpatine.