Billy has the bravery of a German Shepherd and gentelness of a Golden Retriever, and the loyalty of both breeds.
He's the dog of Takeru Taki.
Takeru trained Billy for more than two years as a fighting dog. When the match came, Billy got his opponent, the debut for a one year and two-month-old Tosa dog, Unryū . Billy was victorious at first, but Unryū’s fighting dog instincts woke up in a fight and it got a grip on Billy’s throat after fifteen minutes. The match ended when the time was up and the dogs were separated, but Unryū had killed Billy who had refused to seri as he had been tought.