Seiren is the mother of Musashi and sister of Burai. She was a very powerful Tosa and earned the title of Yokozuna. She is one of the very few fighting dogs to have tied with the legendary Tosao. At Samon's Safari Park, Seiran confronts Sahara but loses, nearly dying. She appears later when Yamato and Musashi were fighting against Sahara, and before her last breath, she utters a mighty roar that awakens her cowardly son, Musashi's fighting spirit.