The Cultivation World had an old saying: "The Yin spirit is easy to cultivate, but the lightning tribulation is hard to overcome."
Perfecting the Yin spirit only gave one the ability to undergo the lightning tribulation. Whether one could actually survive it was another matter entirely.
In fact, if someone in the Cultivation World attempted the lightning tribulation as soon as they perfected their Yin spirit, fewer than one in ten would succeed—not even one in ten!
How terrifying was the lightning tribulation?!
It was the might of heaven and earth!
It was a trial imposed by all of heaven and earth upon cultivators who defied fate through cultivation!
Failing the trial was the least of one's worries. Death was the easy way out.
In most cases, failure meant one's soul was utterly destroyed! Reincarnation was out of the question!
Once someone survived the lightning tribulation, however, the spirit within them would give rise to Yang from Yin. As Yin and Yang merged, their spirit would no longer be purely Yin. At that stage, even if it were scorched beneath the blazing sun, it would suffer no harm.
Furthermore, the Yang Spirit gained many abilities at this stage.
For instance, one could cultivate an External Incarnation, or send one's Yang Spirit traveling beyond the body. It could move at an absurd speed, touring the northern seas at dawn and Cangwu by dusk, soaring through heaven and earth in boundless freedom.
Most importantly, every cultivator cared about this one thing:
A Yang Spirit could live for more than two thousand years. And even when its lifespan was nearly exhausted, it could still seize another body with its Yang Spirit and reincarnate to cultivate anew.
After successfully surviving the lightning tribulation, Hao Shuai wasn't in a hurry to send his Yang