The supporting character's harem is very normal - Chapter 455 Why?

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.

This is a story about Gong Lixin who was the young master of an ancient underground palace in the ancient times. He was raised by his master and forced to partake sexual relationships with numerous people to cultivate his Yin Body. His master who has a Yang Body was going to absorb him after he has reach a level to become stronger. MC refused and killed his master also dying at the same time. Then he transmigrated to the modern time and thinking he will enjoy peaceful life, the end of the world arrived.

Being someone with no special powers except for his martial arts, see how he use his martial arts to dominate the times and find his lovers.

- Description from Novelupdates

On the surface, he is the aloof and standoffish patriot whose sole purpose is to serve the nation. On the darker side, he is an invincible, powerful and mysterious man.

Reborn Holy Soul Village, nicknamed Aman, the eighteenth generation of ancestors innate soul power zero, awakened third-level green hatchet, no soul ring, no soul skills, fights rely on flat cuts, if you feel uncomfortable, come and cut me.

Also known as “I was born a commoner, a rich family daughter fell in love with me” “This person clearly wastes martial arts…

- Description from novelbuddy