Juubee-chan: Lovely Gantai no Himitsu

Synopsis

While Jubei II fights Shiro/Taiko Daiyu, Koinosuke explains everything to the rest. Jubei II is exhausted and nearly killed by Taiko Daiyu, but Shiro takes over his body and holds back the thrust. Jubei defeats him and Taiko Daiyu's spirit leaves the body. She tells everyone that she cannot return when Taiko Daiyu still exists. Sai lets him to take over his body and fights Jubei. During their battle, Sai's spirit jumps out and grab his daughter's spirit while Jubei II destroy Taiko Daiyu. Though they have won the battle, but Koinosuke left. A few days later, the heroes celebrate the formation of The New Student Lovelies, Jiyu looks at the Koinosuke whistle and says she'll blow on it when she wants to see him.

(Source: Wikipedia)