Eiko Teruya is one of the main protagonists at the end of Demon King Diamao. She has green hair and is the Daughter of the head of the Teruya clan. She just transfered to the school but seems to know what Etou Fujiko is up to. She also states that she was just going to tease Sai Akuto a little but now that she knows he is cute he will be seeing a lot more of her. She also stated that once she gets attached to something she can't leave it alone.