He is a tenth-generation descendant of Gaō.
Reima is a huge, magnificent black-and-white Hokkaido Wolf.
He has a darker muzzle and stripes on his face.
He later loses his left paw.
Reima is charismatic, wise and polite old wolf.
He has sense of honor and once mentioned that he has never killed a female or puppy. However, he may turn angry when disobeyed or betrayed and he takes the honor of warriors very seriously.
Ginga: Nagareboshi Gin
Reima was born as the heir of the Underworld Kingdom. His father was the ruler of wolves.
When Reima was still a puppy, his parents were killed and his home (the Underworld) was taken over by the enemy pack, Soldiers of the Empire. He swore to get his kingdom back, with the help of the legendary hakkenshi of Sirius.
Reima created a new lair for him in the cursed forest of Mount Fuji. There he collected and trained the Warriors. He also adopted Hyōma, posing as his real father.
Reima enters Gin's territory and lures the dog into his lair by kidnapping Cross and Ken, George, Minnie and Chibi, after hearing that he knows the ancient technique of the wolves. He tells him about the situation and Gin is ready to help him. When the group enters the Underworld, the leader of the Soldiers of the Empire, Gaia, attacks. Here Reima attacks Gaia, but the wolf tears off Reima's left paw. Then Gin interferes and fights Gaia, but is soon overpowered by the wolf. When he is about to get killed, Reima, despite his injury, leaps into the fight and protects Gin. While Reima and Gaia fight, an earthquake shakes the rocks at the sealing of the Underworld loose, and Reima is buried in a landslide of rocks. He says his last goodbyes to his soldiers and dies silently.