Demon Sword Maiden - Chapter 67Book 12: : Lily’s Promise (part 1)

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

"The boy has no powers," they claimed.

Imperial soldier Suldak Helansa joined the infantry regiment of the Grand Duke Newman in Bena province, participated in the Warsaw plane war, and rescued a young man in the forest battle. This qualified young man suffered some injuries. Injured, still a mute, Suldak brought him into the barracks, and what we are telling is the story of this young man of unknown origin…

- Description from novelbuddy