In This Life, The Greatest Star In The Universe - Chapter 125:

The mysterious force known as the Essence Record finally descended upon Earth, tearing the world asunder and reshaping it through chaos and evolution.Cities turned to ruins. Animals mutated. Some humans lost their minds, others became monsters. Only a few survived the Awakening… and were granted the right to evolve.A new world was born, where the old rules meant nothing. The only law that remained was survival—where hesitation equals death.Adam, an ordinary college student, finds himself alone, far from home, in a world no longer built for the weak. His only goal: to find his family—if they’re still alive in this broken world.No god, beast, demon, man or zombie shall stop him. As long as he draws breath, he won’t stop.

From the outcast of the imperial family to the emperor, Wei Chongrong’s path to the throne took thirty years.

In his previous life, everyone thought that he shouldn’t exist.

Only his youngest uncle was good to him, so he went through fire and water for him.

But what he ended up waiting for was the poisoned wine poured for him by the youngest uncle’s own hands.

Starting over, Wei Chongrong, who is familiar with the future, finds that the road ahead is still bumpy.

The battle that is bound to be lost is about to happen, and the scourge of witchcraft is close at hand.

What can he do to save the Eastern Palace and the imperial family, and to save Jun Hua, to whom he is indebted for a lifetime?

- Description from Novelupdates

He possessed the Xuan Gate Medical Arts and had fortuitously obtained a heaven-defying Spiritual Treasure!

This legend tells the tale of the protagonist, Kuroki summoned to protect the demon king from the hero.

Kuroki, unbeknownst to him, suddenly came to another world. He was summoned by the demon king, Modes. The territory which the demon king overrules was in the midst of being destroyed because of the hero. He had no choice but to bow before Kuroki.

“Please save us, Savior Dono!”

Kuroki nodded, deciding to save the demon king due to an unexpected turn of event.