Kai

is a young wolf demon, who lived in the northern tribe with his younger brother Shinta.

During the story
Forced to flee his home with the rest of the tribe, Kai watched as the rest of his comrades were slaughtered by a vicious badger demon under the command of Byakuya. Only Kai and Shinta was saved. Byakuya gives Kai a chain weapon and a Shikon shard, then orders him to murder Kōga and bring back his shards in exchange for Shinta's life. Though he is unable to so much as wound Kōga, Kai runs back to his meeting point with Byakuya as the deadline was sunset; Kōga followed, and Byakuya said bringing Kōga himself is works as well. However, Shinta was sent off with a moth demon that sent out tons of demonic energy; this attracted Mōryōmaru, who almost swallowed Shinta along with the moth demon. Rescuing his brother, Kai lost the shard Byakuya gave him, and Mōryōmaru became stronger thanks to it. In the Final Act, he and his brother attend Kōga's wedding with Ayame.

Personality
Much like any other wolf demon, Kai cherishes his comrades and directs anger at whoever is responsible for the slaughter of any of them. He cares for his little brother, always looking out for him. Kai blamed the wolf demon tribes being attacked on Kōga, who was supposed to be their leader, but was off looking all the time looking for Naraku; he didn't know he was trying to avenge the deaths of their comrades. He later gains respect for Kōga after hearing about his goal, even attending his wedding in the anime.

Physical description
Befitting his name, Kai has grey/silver hair with pale teal eyes. As demons age differently than humans, it would be hard to guess his age, but Kai looks similar to a pre-teen. Being too young to wear armor, Kai wears a one-piece outfit made of fur; he uses a black piece of fabric to tie it at his waist. Two tufts of fur come off his collar, similar to a scarf. He also wears black bands on his lower arms.

Kai 小灰