Shen Lian's fire could burn down plants, crack rocks as tough as steel, and boil the endless flowing river water dry. However, it could not cause any damage to the bodies of the Vajra Jiedi.
There were also born from flesh but it happened to be that they were tough, close to being indestructible.
Shen Lian could deeply feel that the sixteen Vajra Jiedis were that way because of the abnormalities of their body structure, and each of them had an unspeakable Dao rhythm, which was the 'Vajra'. As the saying goes, 'Those that could not be destroyed was the ultimate resistance, and those that could not be replaced was the ultimate Dao.'
This was the ultimate 'Dao' of the gold element, it was also the 'Dao' of the mortal world derived from forging through brambles and thorns. Unfortunately, the master of these Vajra Jiedis did not have a profound understanding of the essence of this strength. He only had its power but not its technique and its usage.