Riki, Weed's grandfather and Gin's father, was born a runt. His father was Shiro and his mother was Yamabuki. When Gohei, Shiro's owner, came to select a pup from the litter, he paid no attention to Riki. Consequently, Riki was never rehomed and grew close to his mother. Unfortunately, Yamabuki's true owner, who had been ill, recovered enough to reclaim her. Feeling unable to manage two dogs, he decided not to take Riki in. Riki missed his mother deeply and one day set out to find her. During his journey, a pack of dogs attacked him. Hopelessly outnumbered, Riki attempted to escape and fell into a river. Upon waking, he discovered that his father, Shiro, had rescued him. Although Riki had never seen his father, he knew his name. Shiro, however, was unaware that Riki was his son and left before Riki could speak, though not before delivering a speech on the importance of strength. Riki made it his goal to constantly grow stronger. One day, a child named Daisuke drove a ride-on toy car through a mountain pass with an incline. Riki, who was traveling to see his mother, noticed him racing down. A truck driver, failing to see Daisuke, struck the boy and sent him flying over the road railing. Fearing the boy was dead, the driver drove away. Daisuke, though only bruised, was unconscious. Riki jumped onto a ledge and howled, hoping someone would hear. Instead, the pack that had previously attacked him heard him and arrived. Having grown to hate humans due to past abuse, the pack attacked Daisuke. In an effort to save him, Riki fought the dogs and succeeded. Gohei and Shiro eventually arrived, causing the pack to flee. Shiro finally learned that Riki was his son. Gohei, Shiro, and a few others set out to fight Akakabuto. Seeing this, Riki followed their van. Gohei intended to kill Akakabuto, but the bear proved too strong. Gohei shot the bear in the eye, and the bullet lodged in the beast's brain. This drove the bear insane; while biting Shiro, it fell over a cliff. Riki witnessed everything and was distraught when his father fell. These events set the stage for the future series, Ginga Nagareboshi Gin.