After Tian Shu and Tian Miao blew themselves up, the gold energies and water energies they formed were collected by Ling Xiu, who turned them into a cluster of black mist and golden mist.
It was very difficult for golden spirits and water spirits to be born, and even more so for them to become saint kings.
Take Tian Miao as an example. She was originally a trace of origin Qi of water spirits under a saint lake. After hundreds of years of absorbing spiritual Qi and essences from the sun and moon, she gained a bit of intelligence.
After being instructed by a great being, she started to refine.
Only after countless years of refining was she able to form a human body, after which her refining speed got faster.
Because of all these years of refining, the origin Qi of water spirits that formed her body was a true treasure among the Five Elements Valuables.