Kiyoomi doesn't know who he is, all he knows is his name is sakusa kiyoomi. He can't feel emotion, and he doesn't know anything, he doesn't even know how to speak. He can learn, very easily. He observes things and takes what he observes and uses it to learn. He's like a blank slate waiting to use things around him color in who he is. He isn't anyone, he's waiting to take information and make himself someone.