Kumi is Rihito's mom. She ends up hospitalized before surgery, and Rihito basically becomes her full-time caretaker—visiting every single day while somehow juggling school and cram school on top of everything else. She's supportive of Rihito and Hikaru being together, which is nice since Rihito clearly cares what she thinks.
Content compiled by AnimeList.moe from publicly available sources.
