A giant fortress inside the Primordial Profound Ark that moves around on its own. It is so big that you cant see its borders at all. This was the place Yun Che was forced to hide in while he was hiding from Ye Xinghan with Feng Xue'er. The walls are so strong that not even a Mid Level Tyrant Practitioner with a Tyrant Profound Weapon at full strength or spatial tears can leave a scratch on them. The rooms have a special locking array that can only be unlocked from the inside, keeping everyone outside.

Later Yun Che was found by a Lingering Soul that was looking for the Sky Poison Pearl, who lead him to find the Coffin of Eternity with Hong'er inside of it.