Persia's childhood friend in the White Cats House. She is one of the people who is aware of Persia's secret romantic relationship with Romio Inuzuka.
Chartreux is quite sadistic, and takes pleasure in using others as tools. She likes using others as a 'play things', in which she orders them around to do activities such as acting like animals. Her sadistic and terrible personality is what gives her the nickname 'The Tyrant Princess of the West'.
Besides her sadistic nature, she also has a burning lust for Persia. While she treats Juliet happily, she treats Inuzuka in a cold manner; not only is she jealous of Persia and Inuzuka's relationship, she also reassures to keep it a secret.
(Source: Boarding School Juliet Wikia)