Tokuko Sharekoube

One of the legendary Four Lords of Pastimers, she is a student of a prestigious nearby all-girls academy and introduced by one of Chisato's friends - a teacher at that school. She dropped by during Episode 4 to socialize with the Pastimers Club.

Her name is revealed in chapter 73, as well as the fact that she has multiple talents such as performing rakugo and playing the koto.