My Black-Bellied Boyfriend - Chapter 4

I got transmigrated into a game I’ve never seen before.

I thought it was a top-notch RPG and spent 30 years on it.

I retired as a war hero and planned to spend my remaining time leisurely.

But it turns out, it was an academy story?

An Individual from Earth finds themselves in the Shinobi World, equipped with a Scientific System. From that moment, he delved into scientific research far ahead of its time.

The Zhuang Lady sent her dog, Yin Huayue, to keep an eye on him and confine him. She is cold-blooded and hypocritical, and always has a fake smile on her face. Helping him get ready, combing his hair, and lighting the lamps. Awake for twelve hours a day, Li Jingyun spends ten hours thinking about how to make her leave. But after that, she actually left. He became anxious.

Despite our brief time together, we are not appreciated despite our strength. Rather be alone, instead of withering alongside with another.

- Description from Novelupdates

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.