Varaharu—called "The Monster" in Saiyuuki Reload Gunlock—is a youkai that's been possessing Hazel since childhood, though Hazel himself doesn't know it. The possession is actually the source of Hazel's soul-moving and soul-swapping abilities.
Varaharu showed up when Hazel was a kid. The youkai chased him down, and Hazel, who'd grown to hate monsters after his parents were killed by them, tried to kill it. Instead, the monster cursed him by forcing its way into his body. When Hazel's master Filbert Grouse found him transformed and monstrous, a berserk Hazel killed him in the struggle. But before dying, Grouse told Hazel he needed to let go of his hatred and find someone who'd understand him.
Years down the line, Hazel met Gat. The moment their paths crossed, Varaharu took control, transforming Hazel into a monster again. Gat killed him—but the instant Gat closed Hazel's eyes, he saw Hazel's painful memories. That's when Gat made a spiritual bargain: he offered his own soul to bring Hazel back. After the revival, a spirit sealed away both Hazel's past and the monster inside him. The seal held as long as that spirit was alive.
Once the spirit finally died, the seal broke, and Varaharu emerged.
Content compiled by AnimeList.moe from publicly available sources.
