Keishi Harumoto (東本 桂士 Atsushi Higashimoto) is a 3rd-year communication year student and, technically, a member of the Singing Club. He is a ghost member who is in the singing club at the request of Mitsuki Akika, but no one has ever seen him. He is an IT expert and enjoys human observation by hijacking security cameras.
Keishi wears a tan-colored sweater that is rolled down on one side of his shoulder with a black undershirt, and dark blue pants.
The ghost member of the singing club. Due to his hikkikomori tendencies, he is hardly seen at school and will usually only talk to Mitsuki Akika, making him quite an introvert.
He is very asocial but will do his best in assisting his friends if needed, as long as it doesn't require him to go out or exercise.
Speaking by telephone, Keishi is still observing various scenes via cameras. One such camera is monitoring Saku Otonomiya, seemingly through a cat.
- Favorite: Dietary supplements
- What I like: Human observation without human beings
- What I'm not good at: Exercise
- "We might be able to use him." (To self)
- "Oh? And are you two having fun?" (To Chiguma Marume and Minori Shido)
- "Looks like he's starting to access it." (To self)
- "That's why I was against this, because I knew something like this would happen." (To self)
- "I guess I don't have a choice." (To self)
- "Did they crossover?" (To self)
- "I'm just... me." (To Mitsuki Akika)
- "Do whatever you can to make it a success." (To Mitsuki)
- "I want you to hype it up even more than previous years." (To Mitsuki)
- "But they aren't just data! They exist and continue to grow!" (To the Japanese government)
- "Mitsuki, I'm counting on you." (To self)
- "They might be just what we need to turn this around." (To self)
- "I'm the one who needs to apologize." (To Mitsuki)
- "I haven't been able to do anything." (To Mitsuki)
- "They are all individually unique!" (To the Japanese government)
- "If Mitsuki's not going to give up, neither am I!" (To self)
- "In order to save your sister and your world... You need to put... the fact that you're alive... and your lives... have meaning into a song... and let the people... in the outside world... know your worth!" (To Saku Otonomiya)
- "The days you've lived are yours and yours alone." (To Saku)
- "Since you had the nerve to call them just data, I'll show you what that really means." (To self)
- "They really are amazing." (To self)
- The name Keishi means "Japanese Judas-tree" (桂) (kei) and "samurai, warrior" (士) (ji/shi).
- Keishi's surname Harumoto means "east" (東) (haru) and "base, root, origin" (本) (moto).