Akane Koganei (小金井 茜, Koganei Akane) is Shinji Koganei's older sister.
Akane has brown mid-long hair that are held back with a hairband. Like her brother Shinji, she has a cat-like mouth.
As Shinji's big sister, she is sometimes rough to him but she is very supportive.
During Shinji's first year at Seirin, Akane learned from him that he'll try basketball. Exasperated, Akane reminded him of the multiple clubs that he tried and that he should try to stick to one instead of changing all the time. Shinji claimed that he'll stick to basketball before running away.
Akane makes her first appearance on the day Seirin plays against Too during the Interhigh. While brushing her teeth, she hits his brother, who's still sleeping, to hurry him up to prepare for school.
Akane shows up in Shinji's room, telling him that he is only one step away from winning the Winter Cup. She asks if he is gonna be playing but he is not sure since he is not a starter. Akane then remarks that he was not the same back in middle school, where he would only complain about not playing and didn't even cheer for his teammates. His mother would always scold him afterwards. Shinji answers that he wants to play but that his team winning comes first. Satisfied and happy, Akane exclaims that she'll bring the entire family to watch him.Akane later goes watching the Winter Cup final. She is seen cheering herbrother, who goes up against Mibuchi. She overhears the crowd saying that he has little chance against an Uncrowned King but she stands up, shouting for him to stop his opponent no matter how strong he is.