Ginga Densetsu Weed Manga
He only appears in a flashback where he was always abusing Kyōshirō and his siblings as well as his mother. His oldest son Fuyuto, bit his ankle to get him to stop abusing his mother, but he just grabbed him and threw him against the rocks causing his death. The vicious male continued his abusive ways and no one in the family dared to stand against him.
A bit later, a traveling dog noticed how badly the puppies were treated. He offered the father a boar to have the puppies. The father accepted the offer and the traveler adopted the 3 puppies including Kyōshirō.
About 6 months later, the puppies heard that their mother is ill, caused by the stress. The three siblings tracked down their father, believing he killed the mother and deciding to kill their father. The 2 older brothers committed a suicidal attack by pushing themselves and their father off the cliff.