Ishida's older sister. She is significantly older than him as she already graduated from college when he was still in elementary school.

Curiously, she is the only character with lines whose face is never seen; even her husband and daughter are shown and get more screen time than her. According to Ishida, his sister had dated numerous men, one of whom has a younger brother who was bullied by Ishida; this event probably led to his breakup with her. Later, she dated a Brazilian man named Pedro, this time, her relationship stuck and she had a daughter, Maria, with him. The final chapter reveals that she is expecting her second child with Pedro.
(Source: Wikipedia)