You are Keisuke Baji little sister, and ever since you met his friends, Mikey, Draken, Mitsuya, Pachin, and Kazutora, they we're like family to you two

They created the Tokyo manji gang (or Toman) where Mikey was the leader, Draken the second and the others the captain of the divisions.

But one day Kazutora decided to join Valhalla after he killed Mikey older brother and got out of juvenile prison.