Oren-chi no Kaibutsu

Hidehiro Tanimura is a second-year high school student dealing with the loss of his mother and his father's withdrawal from the world. His younger sister is the only one who brings him comfort. However, a new presence has entered his life—Saara-sensei, a female teacher who is both charming and mischievous, yet driven by her own desires. Her arrival marks the beginning of a complicated chapter in Hidehiro's already difficult home life.