Vocaloid: Ishiko Yoru

Ishiko is just another normal high school girl (not counting a missing eye because I'm putting it like the eye color is black you jerks.) until the world is enveloped with chaos and everyone is turned into demons. Her father becomes a demon overlord and she is the only daughter. She was also turned into a demon which changed her left eye color to black. She is summoned by a family and she discovers that the rather odd person is the only human in the world.