Chitose

Chitose serves as the teacher who educates the protagonists Yoko and Eri within the shelter, and is affectionately called 'big sister' by both of them. As the pivotal figure who sets the two on their journey, she left behind a record known as 'Touringram.' She appears primarily through screen communications or video footage, offering encouragement and guidance along the way. Her true identity and background remain one of the central mysteries of the story.