Mahata Shuka

Her parents raised her in a strict household and provided her with many opportunities to pursue non-academic interests since she was young. Although she occasionally enjoyed the activities she was forced to learn, she was also barred from enjoying simpler distractions like anime and the like. One day she realised that her parents didn't really see her for what she was, since they were never there for important occasions like the final of a music competition, the opening day of school etc.

Shuka was also interested in sex as well, but her parents dismissed her and barred her from talking about it saying such acts were filthy. However, Shuka accidentally witnessed her parents having sexual intercourse, which was both a shock and a huge betrayal for her given their previous remarks.

To relieve the stress of her parents' lack of concern and all of the things she was forced to do since young, she dresses up in her provocative clothing and taunts middle-aged men on the trains. Kiichi is one such victim; she baits him into molesting her on the train which he takes up. When she tries to extort him for money after the act is done, he refuses and she calls the police on him.

Kiichi escapes and vows to show her how dangerous her man-baiting hobby is. When his revenge is somewhat completed, she tells him why she engages in her particular hobby and asks for his help in changing her current relationship with her parents.

If she is not sent on the ark, her plan to change how her parents see her with Kiichi's help succeeds to some extent. Although her parents have completely given up on her, she's grateful for her newly won freedom.

Her cheeky attitude extends to Kiichi as well. He absolutely hates it when she calls him "Uncle" since the age gap between them would make "big brother" more appropriate.