Harusame was Utakata's former master. He once tried to extract the Six-Tailed Slug from Utakata's body, but the procedure went catastrophically wrong—Utakata transformed into the Six-Tails and killed him in the process. The incident left Utakata deeply traumatized and convinced that the master-student bond couldn't be trusted.
There's some disagreement about Harusame's intentions. According to Tsurugi, he was actually trying to save Utakata by removing the beast. Utakata, however, sees it differently and believes Harusame had other motives. Either way, his death became a defining moment in Utakata's life and shaped how he viewed relationships going forward.
Content compiled by AnimeList.moe from publicly available sources.
