Beast Taming: Infinite Simulation as a Tamed Beast - Chapter 36

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.

A tree of 10,000 flowers, the world is the door.
The spells change a lot, but the hearts of the people are unchanged.

- Description from Uukanshu translation

A story about a weak, small larva with a human soul, who travels all the way to become the ruler of the stars.

My grandfather is very eccentric, performing daily rituals of offering incense to himself, standing in front of his own spirit tablet and eating candles.Villagers are fearful of my grandfather.I am fearful of him too.Later, I discovered that what they were afraid of was not my grandfather, but me.Even grandfather is afraid of me....My name is Chen Shi.The Chen of honesty, the Shi of sincerity.