The Strongest Gene - Chapter 4: To Hell with It!

As a man who had lived for 20 something years and had always considered himself as a straight man, he woke up one day and found himself possessed by a stupid and cute system. Moreover, it was a gong-shou cultivating system?! Let’s see how a shou with raised hackles evolves into a (pseudo)queen shou, incidentally with a story of a hidden loyal dog gong.

- Description from Novelupdates

Who needs a Class when you're already the strongest anyways?Ten years ago, Amelia woke up alone and lost in a broken world where she had to fight for her survival.Now, after reaching the pinnacle of power, defeating the Void itself, and escaping the abyss, she has finally found her way back into the real world. But instead of returning to Earth, she arrives in the land of Vacuos. A fantasy world with magic, monsters, Classes, and Levels. A world that is governed by a System like it were a video game.And when rewarded with a Class befitting her accomplishments— to become a powerful [Hero] that will forever dedicate her life to protecting this world that is not her own— she only has one response.“Absolutely not. I’m going to live a normal life now, thank you very much.”

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.