Mizuchi Miyadeguchi is a character from the Touhou Project, appearing as a vengeful spirit associated with the Hakurei Shrine in Touhou 17.5: Sunken Fossil World. She is portrayed as a lingering, resentful presence tied to past conflicts and the spiritual imbalance surrounding Gensokyo. Mizuchi serves as an antagonistic figure whose actions drive the story’s conflict, confronting Reimu Hakurei and others with her hostility and mysterious motives. Her role emphasizes the series’ themes of spirits, grudges, and the unstable boundary between the living and the dead.