Sakuma has short dark-coloured hair and also dark-coloured eyes. He wears the school standard male uniform.
He was described by Tachibana as an unpopular boy with mature feels. He couldn't resist as the non-existent student because of the pressure and rejection.
He appeared in Tachibana's flashback from the chapter 11 of the manga. When she was at school, suddenly she heard Sakuma saying " I do exist, I'm right here, I exist". After semester 2, because of the pressure and rejection, he broke the agreement. When the new year started, he commited suicide.
- His surname, Sakuma, may come from a profession, such as the name "Fisher" which was given to fishermen.
- He is mentioned in the anime.