Aoi Ningyou, known as the 'Blue Doll' (青い人形) in the game Ib, is a recurring, mysterious character encountered in the surreal art museum. The Blue Doll appears as a haunting, blue-hued doll that acts as both an obstacle and a guide, often blocking Ib's path or providing cryptic hints. The doll embodies the unsettling atmosphere of the game, representing the twisted nature of the gallery and adding to the psychological tension experienced by the protagonist.