Ghost in the City: Cyberpunk Gamer SI - Chapter 9

He is the ruler of the mercenary realm, an overlord that gives headaches to the leaders of any country! For the sake of his friends, he’s willing to sacrifice himself; for the sake of his family, he does not hesitate to spill blood! He is a dragon, one that soars above even the highest of heavens. He’s a power that advances triumphantly through unstable situations, stirring up both the winds and the waters.

However, he did not know that he was not raising just a harmless pet, but a biological weapon secretly made by the government… a real monster.

As a former librarian, Rand felt that he had been living an ordinary life, the one that he had reclaimed unconsciously every single day.

Recently, he has been a little upset because the pet fish he accidently brought home to raised seems to have undergo some strange changes

Well, it turned into a merman.

- Description from Novelupdates

Soldier King Li Qiang, who was part of the Special Forces ace army's Winged Dragon commandos, had accidentally broken the relationship between his fiancee and his adulterer and had lost his life because of this! Under the effects of the treasure, he was reborn as a normal high school student, and actually discovered that the school beauty, Lin Ya Shi, was the daughter of his fiancee and his adulterer. In order to take revenge on his enemy, he used the opportunity to get close to the Lin family while the school beauty was his bodyguard, but he discovered that a huge crisis was approaching everyone …