A Record of Ash & Ruin: The Grieving Lands - Chapter 14Book 1: : The Characters of a Slave

A loner boy, who’s always loved escaping into his RPG world, suddenly finds himself living as one of his game characters. But instead of becoming his favored fighter, he’s in the body of his second avatar—a support mage! Though he’s used to playing both roles, being the mage in real life is a whole new challenge. Now he must rely on his knowledge and skills to navigate this unfamiliar reality and survive as the game's “support.”

A former sporting rifle shooter genius transforms into the ‘Juvenile Butcher’. While originally supposed to have received the death penalty, he was instead fortunate enough to have entered a secret and highly regarded armed force, throwing himself into the ‘Nirvana Project’.

After a period of 10 years, he now has time to freely recover. Having trained until he had excellent military and martial skill, he sweeps through various military districts and returns back to his hometown. Under the monitoring of a beautiful female cop, he re-establishes his family’s bodyguard service, protecting beauties and moving unhindered, his achievements causing the fame of his outstanding, god-level bodyguard service to resound across the world!

- Description from Novelupdates

Shi Jin once read a book. It was supposed to be about satisfying the desire for vengeance.