One of Sawa's classmates and Ran's closest friends. He is Ran's best friend and is one of the firsts to be aware of Sawa and Ran's relationship. He was in the basketball club with Ran and Kido until the third quarter of their second year of middle school. Tsubaki is very caring of Akira. In an omake, Akira reveals that he has two older sisters (it was inside her notepad of research). He is number two on the list of people Akira can't handle, right behind Sawa. Tsubaki wears round glasses.