Nemesis

Birthday: December 31
Height: 142 cm (usual form), 166 cm (adult form)
Weight: Unknown
BWH: 65-51-68 cm (usual form), 91-57-88 cm (adult form)

Nemesis is a sadistic, demanding girl who is responsible in giving orders to Mea. She uses Mea as her spy to look after Yami's changes and recent life. In addition, Nemesis is the one behind the plans to make Yami return to her emotionless-assassin's life again. Claiming that she knows that one day, Yami will return to her real path naturally, she decided to live in the human world and tries to be friends with everyone; in refusal of Momo and Rito. Like the other girls, she also seems to have sexual feelings towards Rito and plans to train him as her "pet."

(Source: Wikia)