Shiro is the mate of Yamabuki, the father of Riki, the grandfather of Gin and Aka, the great-grandfather of Joe, Kinumaru, Weed, Yuki and Yukimura and the great-great-grandfather of Bellatrix, Jirōmaru, Kōshirō, Koyuki, Orion, Rigel, Saburōmaru, Shion, Sirius and Tarōmaru.
In the GNG anime he is a non-brindle silver Akita and wears a dark brown collar.
In the first coloured Weekly Shōnen Jump pages of the GNG manga he is light red with a black collar.
In a newer picture, he is seen as pure white and with a green collar.
Shiro was Riki's father and Yamabuki's mate. He was owned by the hunter, Gohē Takeda, who had trained him into one of the best hunting dogs. Shiro saved Riki after he found him badly beaten up, drifting in the river, and told him how to become great.
On a hunt for the wild bear Akakabuto, Shiro and Gohē Takeda were ambushed and needed to struggle for their lives. As Riki rushed in to help, Shiro saw an option to save his owner and his son by pushing Akakabuto and himself into a ravine.
In the start of chapter one, there is a flashback of Shiro and Gohē Takeda hunting Akakabuto. Gohē lost his ear in the battle against Akakabuto. Shiro attackd Akakabuto to protect him and they both fell into the valley, Shiro biting Akakabuto's muzzle. Akakabuto survived, but Shiro did not.
- Shiro's appearance changed three times in total over the time in colour:
- In the first chapter of GNG, Shiro was portrayed as a pale red Akita, similar in appearance to his great-great-grandsons Kōshirō and Saburōmaru.
- In the GNG Anime, Shiro was portrayed as a stripeless silver Akita, similar in appearance to his grandson Gin.
- In a the newest edition of GDR, Shiro was portrayed as a full white Akita, similar in appearance to one of his grandchildren, his great-granddaughters Kinumaru and Yuki, and his great-great-grandchildren Koyuki and Shion.