Chaos Devourer System - Chapter 643: Undying Star Core...

In a monstrous post-apocalyptic setting, this is a story of how a lowly Inventor, Lance, conquered a nation governed by immoral group of Scientists called The Corporation. He grew and climbed up to the highest rank possible as a Scientist with his inventions and side businesses. Eventually, he became a weapons inventor, building weapons to two opposing sides. In doing so, Lance always crossed a dilemma. How could a nobody topple the most powerful government? How could one overcome circumstances beyond his grasp, especially in a world filled with monstrous mutations called the Abominants?

After his qi center is destroyed, a martial arts instructor of the Blood Demon Cult is assigned to learn and research the martial arts of four captured murim masters. However, when the Cult betrays him and decides to kill him, he fights back and everyone in the Cult dies, including himself.He then mysteriously wakes up in the body of Baek Suryong, a young martial arts instructor in the rural countryside with a disease that will kill him within three years. He realizes that the martial arts he had learned holds the key to healing his new body’s illness, but in order to do that, he needed money. A LOT of money.Baek Suryong thus embarks on a journey to become the Star Instructor of the Azure Dragon Martial Arts Academy, and earn enough money to save his own life! Perhaps he would even manage to educate some kids along the way…

The 7-year-old little crybaby met 11-year-old big brother who ran away from home.
[This man became the protector of redemption in his life]

The 16-year-old little dragon fell in love with a 20-year-old big brother.
[It’s a pity that the big brother didn’t recognize him as the little crybaby]

The 23-year-old single father and 27-year-old chief executive meets again.
[This time the little crybaby and his big brother are finally together]

Fortunately we met through hundreds of millions of people, Thank God, for letting us break through many obstacles and get back together again, falling in love with you and being with you again is the greatest fortune in my life.

- Description from Novelupdates

Police officer, would you believe me if I say this is an Iyashikei game?