The pyramid constructed by the Holy Emperor, Souther. It was built by the slave labor of children kidnapped and trafficked from across the wasteland. Shu was killed resting the capstone of the pyramid in order to protect his young charges taken hostage by Souther.
It was revealed by Souther that the pyramid would become the tomb for his deceased master, Ogai, and serve as the final resting place for his attachment. However, after Kenshiro defeated Souther, the pyramid came crashing down under the weight of Shu's grieving spirit.