Kakao Mizushima, 56 years old. A former soldier and full-body cyborg. He is an extreme predator who lives in a luxurious mansion. He is wealthy enough to travel around the world six times over. At night, he removes his suit for a health check. He is an estrus-type cyborg who feels an uncontrollable urge to reproduce whenever a woman is near. Though he appears stoic, silent, and difficult to handle at first glance, he is kind and reliable. He simply loses control of his urges in front of women.