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 survived. Byakuya gave Kai a chain weapon and a Shikon Jewel shard, then ordered him to murder Kōga and bring back his shards in exchange for Shinta's life. Though he was unable to do so much as wound Kōga, Kai ran back to his meeting point with Byakuya as the deadline was sunset; Kōga followed, and Byakuya told Kai that bringing Kōga himself was as good as bringing his shards alone. However, Byakuya sent Shinta with a moth demon that sent out tons of demonic energy; this attracted Mōryōmaru, who almost swallowed Shinta along with the moth demon. In the process of rescuing his brother, Kai lost the shard Byakuya gave him, and Mōryōmaru became stronger thanks to it.
He and his brother attended Kōga's wedding with Ayame.
Much like any other wolf demon, Kai cherished his comrades and directed anger at whoever was responsible for the slaughter of any of them. He cared 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 instead was off looking for Naraku; he didn't know he was trying to avenge the deaths of their comrades. He later gained respect for Kōga after hearing about his goal, even attending his wedding in the anime.
Befitting his name, Kai had grey/silver hair with pale teal eyes. He looked to be around a pre-teen age. Being too young to wear armor, Kai wore a one-piece outfit made of fur, and he used a black piece of fabric to tie it at his waist. Two tufts of fur came off of his collar, similar to a scarf. He also wore black bands on his lower arms.
|Yōkai Wolf Tribes|
|Eastern Tribe||Ginta • Hakkaku • Kōga • Yawaragi|
|Northern Tribe||Ayame • Kai • Shinta • Rōrō • Wolf elder • Wolf demon graveyard protector|
|Unique Places||Lair of the wolf demon tribe • Wolf demon tribe graveyard|
|Unique Items||Goraishi • Kurikaramaru|
|Enemies||Birds of Paradise (Birds of Paradise leader) • Panther tribe (Panther King) • Naraku|