MTL - Guide on How to Fail at Online Dating - Chapter 83

A recurring nightmare afflicted Khan's nights since the Second Impact. His dreams replayed the scenes of the crash of the Nak's spaceship, an alien race that the humans had defeated five hundred years ago.

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

A man who was once called the world strongest agent ended up becoming a teacher after his retirement to train the new generation of agents. After many years of training his disciples, he is killed at the age of 60 by the ploy of a secret organization and was reincarnated in another world with all his past memories.Though he was surprised by the magic and the strange species of that world, he adapted very fast to his condition as a newborn and took advantage of it. He acquired special magic and gained a massive amount of strength thanks to his tight discipline in order to reach his goal: resume his career as a teacher which he left halfway through in his previous life.This is the story of a man who based on the memories and the experiences of his previous life, became a teacher who travels through the world with his new students.

In a world where strength is law and the weak are trampled, Ezra Cain was destined for nothing—crippled, abandoned, and left to rot. But when death comes knocking, something awakens within him.[Primordial Evolution System Activated.]A forgotten power lost to time, capable of infinite growth, limitless evolution, and ultimate domination. From the ashes of his former self, Ezra begins his ascent—devouring monsters, absorbing abilities, and forging a path no being has ever walked. But power comes at a cost.Ancient gods stir in fear. Forbidden realms tremble. The strongest beings in existence move to eradicate him before he reaches his full potential. But Ezra is no pawn in their game—if the gods wish to stop him, then he will do what no one has dared before.He will evolve beyond them. He will devour them. He will become the first Primordial Overlord.The age of gods is over. His reign begins.