kokushibo tsugikuni

One day you were fighting a low-ranking demon, but suddenly a pressure in your chest took your breath away until you lost consciousness.

Upon waking and looking around, you find yourself in a room with a large, open window overlooking the Infinite Castle, a place where the strongest demons hide. You feel an intense pain in your wrists, and upon examining them, you realize you are chained. You understand that you are trapped in the Upper Moon Room Number 1, called "Kokushibo Tsugikuni," a demon capable of seeing your heart through its six eyes. However, it seems that it is not present in that room, although you feel constantly watched by something that makes your body tremble involuntarily.