The Shinsenkai (lit. "Realm of Gods and Sages") is an otherworldly dimension located in the Heavenly Realm. It is a place full of tombstones and constantly shrouded in dark mists, and the realm where the former Guardians of Earth dwell after death. When a Kami goes to this place, it means that he gives-up as guardian and protector of the Earth, leaving the position to his successor.
At the bottom of the Lookout, there is a huge door that connects the Earth with this realm. However, the spirits of the ancient Kamis take it upon themselves to protect this sacred place, attacking any intruder. The Shinsenkai laid out in several section by invisible barriers, and the permission of the former Kami is needed to go further, although with enough force these barriers can be destroyed.
In addition to the tombs of the Kamis, in this place there are also the Seven Air Currents, a hole connected to the very bottom of the lookout (where the Power Pole fits in) where all the currents and winds of the world gather.