Medaka Kurokami is one of the most powerful heroines out there. It is no exaggeration to say that she could easily beat over 90% of fiction. B-Rabbit is strong as well but she is incredibly outmatched in speed, strength, and every other area. B-Rabbit just doesn’t have the sheer abilities needed to stop someone like this. She wouldn’t even be able to slow her down since Medaka’s flash step would immediately get her around B-Rabbit’s defenses. Medaka Kurokami wins.