The altar was actually right beneath the underground space. When Su Xiao had bombed the Rainthroat Tribe earlier, he had already searched this underground space. The ground wasn't made of stone; that section of floor that had just slid aside was clearly carved from a massive piece of metal ore.
This made Su Xiao realize that the place Naji Jia had opened was actually an alternate dimension. The gem-inlaid disc was both the coordinate and the key to that alternate dimension.
For the past few days, Su Xiao had been fighting all kinds of enemies and hadn't had time to explore this world. Naji Jia, on the other hand, had done the opposite. After discovering that this was a clash between immortals, he had begun exploring the secrets of this world. That was how he discovered the altar and the stone disc hidden beneath the roots of the Land of Beginnings tree.
Su Xiao rubbed his eye. A contact lens was fitted over his right eye, and an image appeared before it—the feedback sent by Bubu Wang.
Naji Jia walked ahead. After descending more than a dozen stone steps, he arrived before a stone stele resembling a tombstone. He took out a piece of equipment and placed it beneath the stele.
A half-fluid substance resembling wax seeped from the stele. The equipment in front of it rapidly decayed, eventually turning into scraps.
Naji Jia collected the white half-fluid that had seeped from the stele. This should be white amber. After pondering for a moment, he took out a Soul Crystal.
With a crack, the Soul Crystal shattered, but nothing happened. The corner of Naji Jia's eye twitched, and he felt a little pained. He still hadn't figured out what abilities the stele possessed and was currently in the testing phase.