Mikako Mashima teaches as a secondary instructor at the school employing Kengo Ishizuka. She becomes a target for Kengo once he initiates predatory operations within the old school building. After first focusing on student Morimiya Saki, Kengo broadens his scope to encompass Mashima. Her narrative role revolves around victimization, lacking substantial background details, personal motivations, or character growth outside this framework. Events portray her as one subjected to Kengo's actions inside the abandoned school building.