Santa moves through 1960s Kyushu like a ghost watching ghosts, never quite belonging to either world he guards. The rotoscoped live-action bleeding into hand-drawn frames isn't decoration, it's the show admitting that some stories can't be told one way. What hits hardest is how quietly it asks whether the monsters and the people are even different things, then answers you in the final episode in a way that actually means something.
Santa isn't your cheerful gift-giver. In 1960s Kyushu, he's a hell-bound familiar tasked with policing the line between worlds, and that job makes him nobody's friend. When spirits leak into human territory and humans wander where they shouldn't, Santa shows up to clean the mess. The problem: he's got to interact with both sides, and neither one appreciates a bureaucrat from the underworld doing their paperwork in blood. The supernatural and the mundane collide constantly in this rural corner of Japan, creating an atmosphere thick with dread. Each encounter pushes Santa deeper into situations that blur morality and consequence. He's caught between following orders from hell and understanding the messy reality of creatures and people just trying to exist on opposite sides of a border that won't hold still. What emerges is horror grounded in loneliness and obligation rather than jump scares. Viewers drawn to supernatural stories with teeth, where the real terror comes from impossible situations and flawed beings trying to navigate them, will find something rare here. This is folklore horror with a protagonist nobody wants to meet.