Mafuyu's SEKAI, the Empty SEKAI, is a dead world containing hardly anything in it. There are a few dim rays of light, broken stage equipment, fallen stage truss, and pyramids that are cold to the touch. These pyramids are said to be Mafuyu's feelings.[1] It is possible to get lost in this SEKAI due to its vastness, as well as how similar the place looks. At a specific location, it reverberates sound differently.[2] It is unsure if this applies to other locations of the SEKAI.