Teru's father is an abusive dog who beats his son. When he scolds Teru for not bringing him food, Kyoshiro's pack arrive and attack the dog, then throw him into a river as punishment. As a revenge Teru's father brings two doberman asassins - Lector and Thunder to Kyoshiro's pack. He lets them attack the dogs. When Lecter holds down Teru and threatens to kill him, Jerome and the other Ou dogs encourage him to step in and be a father. He is told to kill Kyoshiro by Lecter, but he attacks Lecter instead to stand up for his son. As he fights he tells Teru he was a coward for abusing him in the past and will fight til his death to protect his son. He begs Teru to forgive him. He eventually dies from wounds when Teru finally decides to forgive him.

Teru's father is mistakely named "Riku" by some fans, but Riku is the name of Kyoshiro's subordinate. Teru's father doesn't have any confirmed name neither in manga nor anime.