He was a discarded son of the Yamato family and twin brother of Yamato Takeru. When discarded by the Yamato family, he was adopted by Kokugetsu Sai and trained by him until the time of his death. From that, Jinka met Tama Youko and became her considerate brother. He agreed to travel with her in order to end the hatred between demons and humans in the world (However Jinka himself hates humans).