Return of the Calamity-Class Death Knight - Chapter 43

Shaymon, the man who has achieved the apex of dark magic, is framed as being a Demon King and is killed.

Ruins stretched across the landscape in the apocalypse after the nuclear war.

Three thousand years ago, gods and Buddhas disappeared all over the sky, and the inheritance of practice was broken. It was not until the ancient civilization was destroyed that spiritual energy recovered. Ten thousand races took advantage of this to invade.

Five hundred years later, the human race gradually rose up and began to fight for control of the land of China, and counterattacked all races.

Three hundred years later, Fang Yi, the Lord of the Great Dao, slaughtered all clans, destroyed all the heavens, stepped out of the myriad realms, and fought against the Dao of Heaven.

In desperation, Fang Yi sacrificed blood to eight hundred small worlds, reversed time and space, and was reborn nineteen years old.

In this life, he wants to live a more relaxed life, perfect his Dao Xin, and conquer the Dao of Heaven again.

- Description from novelbuddy

Ukei Kaito fought a desperate struggle in order to fulfill his role as a summoned hero. He defeated the Demon Lord and saved the very world, only to meet an end filled but with betrayal. The companions that he’d trusted throughout his journey betrayed him and killed him by sticking a blade through his chest.