Naraku Isayama is the head of the Isayama family, a prominent exorcist clan in Ga-Rei-Zero. He adopts Yomi Isayama after she loses her parents, raising her with genuine affection and treating her as his own daughter, to the point of valuing her above biological relatives. Naraku is a traditional and righteous man who serves as Yomi’s moral compass during her childhood, instilling in her a strong sense of duty. He plans to pass down the family’s heirloom katana, Shishiou, to Yomi, selecting her as the successor of the Isayama family. This decision creates resentment among other family members, particularly his niece Mei Isayama, fueling internal conflict. Naraku is also a close friend and ally of Garaku Tsuchimiya, Kagura’s father, maintaining strong ties between the two exorcist houses. As an exorcist, Naraku is powerful and experienced, though he lost his left arm in a past mission. His role in the story is primarily as a supporting figure whose care for Yomi shapes her early life, and his murder at the hands of Kazuhiro Mitogawa marks a turning point that destabilizes the Isayama household and sets Yomi on her tragic path. His death eliminates the stability and guidance he provided, directly contributing to the series’ central tragedy.