Tori no Kyuugaeshi

A boy named Kouta, an elementary student shunned by his peers for his aggressive actions, became angry one evening in the mountains behind his school and threw a stone at a bird. The bird later appeared in human form and told Kouta he would seek "revenge" for the attack. As a result, Kouta was made to agree to obey the bird's commands, and he began visiting the bird each night as required.