He is the father of Teru.
Teru's father looks like a usual unknown mixed breed. He has a torn ear, caused by Kyōshirō. Teru's father's fur is also a pattern of brown and white, and he also has a scar running across his forehead(where his remaining ear is) to his cheek, where his missing ear is. Teru's father's remaining ear is floppy.
Teru's father's personality is quite odd. When he is mad at Teru for supposedly stealing food, he gets extremely angry and abusive. However, when he notices anyone else, especially Kyōshirō, he becomes cowardly and usually takes off running. Teru's father could possibly be bipolar or have mood-swings, being he acts cowardly and afraid, and then angry. Most of the time he is always afraid and is scared of any dog he comes across, especially packs, and he runs if he has the chance. Kyōshirō is the main reason for Teru's father's cowardice, due to the fact Kyōshirō is known to constantly get mad at him for picking on Teru. Before his death, Teru's father shows bravery, tired of being a "useless piece of trash".
Ginga Densetsu Weed
Kyōshirō tore off Teru's father's ear, as he caught him beating up Teru because his meal was stolen. He was almost killed until Weed interfered. This causes Teru's father to seek revenge on Kyōshirō for what he did to his ear, and turning his own child against him. Therefore, he helps Lecter and Thunder by luring Kyōshirō into a trap.
But when Lecter takes Teru as hostage, he attacks Lecter, having found the courage to protect his son and the shame for mistreating him. He is severely wounded and succumbs to his injuries but not before his son forgives him. He apologizes before he dies, leaving his son to cry over his dead body.
It is the change of heart and death of Teru's father that convinces Kyōshirō to join Weed after witnessing the father's heroic death to protect his son, and made Kyōshirō change Kōta's name back to Teru.