Osoi was a genin-level shinobi from Kumogakure who fought his last battle alongside Toroi—a fight that killed him. Years later, Orochimaru accidentally summoned him through the Impure World Reincarnation when he meant to bring back Toroi instead. After realizing the mistake, Orochimaru and Kabuto decided to keep him around anyway.
When the Fourth Shinobi World War broke out, Kabuto threw Osoi into the fight as cannon fodder, using him and other weak reincarnated shinobi to help break seals on his stronger undead warriors. During the chaos, Osoi ran into his son Musai, and the two got to talk before Osoi was sealed away. He finally found peace when the Impure World Reincarnation was shut down and his soul returned to the afterlife.
Anime Debut: Naruto Shippuuden Episode #316
Content compiled by AnimeList.moe from publicly available sources.
