My Runes Can Be Upgraded - Chapter 15

Avo was born to destroy New Vultun. In a twist of fate, he’ll become its only hope for salvation. The gods were the enemy. The slaver. The chains. With dreams of paradise, humanity slaughtered them and stole their powers, opening the path to become more – to ascend. Instead, they nearly destroyed the world. Vast hive cities serve as the final bastions against the crumbling of reality. New Vultun is the greatest of them all, and within its borders, ascenders wage war to determine the laws of existence itself. The world descends ever deeper into ruination. Avo was born a weapon, a slave to his instincts and his masters. He and his brothers were made to burn New Vultun to ashes. Everything changes when Avo gains immortality and becomes heir to an impossible legacy. He must ascend the megacity of New Vultun. He must challenge the very tyrants that usurped the gods. He must finally free the world from chains.

A man who was once called the world’s strongest agent ended up becoming a teacher after his retirement, to train a new generation of agents. After many years of training his disciples, he was killed at the age of 60 by a secret organization’s ruse and was reincarnated in another world with his memories intact. Though he was surprised by the existence of magic and the strange species in that world, he quickly adapted 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 rigorous 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 students.

Yo, Hi! I’m Frank, I made a deal with a demon to pay me some money for receiving a guest for a few days every week.
I had no idea about what I have done.
On May 1st, Conan ‘the God of Death’ came to my house. I was forced to let him in and we get involved in a criminal case.
On May 8th, Bruce Wayne ‘Batman’ came to me. I was forced to follow him to fight crime.
On May 16th, Hannibal Lecter, The Silence of the Lambs, came to my home. I can only say that I really can’t stand my guests.

- Description from Novelupdates