Where do you get that? He's just ruining Kitamis memories of her being perfect and kind. He doesnt have a grand scheme, he just wants Kitami to suffer because he hates him, similar to kitami killing aliens because he hates them.
Overall not bad but I think the way it kinda devolved into yu gi oh card games on motorcycles took away the charm it had atthe start.
Also yakumo was best girl.