Sajima Yousuke is currently a senior at Suzuran High who won his generation's first year war by defeating Moriken during Hana's Senior year. A dazzling freshman convinced that multiplication tables are essential for survival. When he was only in grade school he witnessed the fight between Rindaman and Genji Takiya , he found out later that both of them were students from Suzuran All Boys High School,after this he became obsessed with Suzuran's history claiming that all of the successive generations are his heroes and that if they were printed on posters he'd hang them on the walls of his bedroom. His dream then became to enter Suzuran High himself and test his worth as a man.
A former member of the Hana-Gumi, he didn't mind being just another pawn on Hana's chessboard as he believed in Hana's leadership of Suzuran. He later appointed himself Tuskishima Hana's personal bodyguard.
Sometime during the war with The Manji Empire ,Sajima lost his title of strongest first year to a new transfer student at Suzuran named Rocket. This loss leaves Sajima in a mild depression, due to having high hopes of competing with his fellow rookies ,Todokin of the Armament and Mikuni Yuukyou of Housen.
Sajima challenges Rocket again, this time handing him a decisive defeat, however he suspects Rocket lost on purpose. Later when Rocket looked down on Suzuran by calling it a "trash heap", Sajima takes it upon himself to lecture him on the school's finer qualities.
In his second year Sajima along with his faction looked on as the Final fight of the incoming freshmen's First Year War took place. He is noticeably happy when Rocket finally realized Suzuran's appeal, screaming it's name from the balcony as the freshmen Tyrone and Kuniyoshi charge at each other.
In his senior year, he was seen hanging out on Suzuran's rooftop along with Rocket and Moriken. He was ranked seventh in "Ippin's Game List".