A former artillery officer from an Asian country, he was discharged from the military after a deadly training accident and was later recruited by Koko. He is the only member on Koko's team that has a family. He is put in charge of giving Jonah science lessons. (Source: Wikipedia)
A former police sniper who was once part of the counter-terrorist unit, until he becomes one of Koko's mercenaries. (Source: ANN)
CIA paramilitary operations officer plotting against Koko. Commits suicide before being bombarded by Koko's jets after R's death.
Natsu Takasaki is a member of Southern Tennis Club (STC). She is in the same year and high school as Maruo. She is aiming to become a professional player. Currently in season 2 and the manga, she's going out with Maruo Eiichirou. (Source: Baby Steps Wikia)
Ryuhei Aoi is a coach at Southern Tennis Club and primarily assists Eiichirou Maruo on his journey to become a professional. He is a ex-professional tennis player who retired after receiving an injury. Ryuhei has a calm personality and likes players to take it easy while working hard. He advices Eiichirou to depend on his instincts and knowledge both or he will lose all his skill and end up being weak. He also cares for his students and when stopped Eichirou when he tried fast serve without any prior training. (Source: Baby Steps Wikia)
As class representative of 2-C, Hanai takes his duties seriously, always trying to keep his classmates (especially the males) in line. Unable to have second thoughts, he always says exactly what comes into his mind regardless of the consequences. He is hopelessly in love with Yakumo, so strongly that she can read his mind literally from a mile away. As a child, he was shy, weak, and always been bullied by other children. That changed with a little help from Mikoto, who has been his friend since that time. He attends the same dojo as her and has a black belt in Kenpo as well. He tries very hard to join the Tea Club that Yakumo is in, but is banned by Akira. Despite Hanai and Mikoto having their own love interests, characters around them sometimes think that they are too close to be just friends. Some of his classmates like Yuuki seems to have a crush on him.