The passage inside the cave sloped downward, twisting and turning. Aside from the occasional dragon roar, fine dust would sometimes shake loose and fall, giving the place the feeling of a dangerously unstable building.
The air inside the cave was extremely dry. There was none of the rank animal-den stench one might expect; instead, it smelled of pine resin and burning grease. It made Silver White wonder whether the dragon called Shou Lao was grilling meat in there.
In truth, Shou Lao normally had nothing to eat. This cave was K'un-Lun's absolute forbidden ground. If the Jade Emperor had not brought the two of them through the restrictions, outsiders would have been unable to enter even if they saw the cave sitting right there.
The importance of the Iron Fist trial to K'un-Lun went without saying. Though the curse of immortality had both benefits and drawbacks, martial artists generally valued their own strength more highly.
There were not many ways to surpass human limits, and killing Shou Lao and bathing in dragon blood happened to be one of them. Shou Lao also happened to be trapped in K'un-Lun and unable to leave. Failing to make use of that would have been a waste of a gift from heaven.
His relationship with K'un-Lun was rather complicated as well. Put simply, they were probably using each other.
Thanks to K'un-Lun's rules, people did not come challenge and harass him every day, which gave him some peace and quiet. As for the Iron Fist trial that came only once every few decades, it was merely one fight. If he lost, at worst someone would take away a share of the concept of his immortality, and he could simply wait to revive.
As for what exactly the curse of immortality was? Even K'un-Lun could