Tsuchimikado Bishu

Tsuchimikado Bishu (土御門美秋), born as Urabe Bishu (卜部美秋) is a woman from the Church of England who was forced to change his family name in order for him to play the part of being a family of Tsuchimikado Motoharu, along with Ashiya Touzu.

She is the one who suggested in Motoharu adopting a girl to pose as his sister.

Etymology
His name is part of the theme of the Tsuchimikado family being based on seasons. Part of his name (秋), can be translated as autumn.

Background
After Tsuchimikado Motoharu was tasked with becoming a spy for the Church in Academy City and becoming an esper. Bishu was apparently tasked to play the part of his family as well, not liking that she is forced to change her name. Bishu is the one to suggest to Motoharu to get adopt a sister from some orphanage outside the city in order to fool their intelligence department. Motoharu doubts it could work and that they would be outed in a matter of three days, though Bishu states that three days is enough for the world to be changed.

Quotes
come with it... In other words, a family."''
 * (To Motoharu, from NT 7) ''"If you are to fake your identity as a student, you must have all the relationships that
 * (To Motoharu, ibid) "Three days is long enough for the entire world to change."