Monster Girl Menagerie - Celestial Archive - Chapter 64 - 62 - Can Your Dog Aplogize?

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

A continuation from where High School DxD Volume 25 left off.

Leon was your typical guy, perceived as weak in his school because his skills hadn't awakened, even though they usually did at the coming of age. He attended the prestigious Milham's Magic Knight Academy, where snagging the top spot meant automatic entry into the esteemed position of a Magic Knight in the country. Unfortunately, Leon found himself in the lower caste, labeled the most useless student. To top it off, he was tossed into a class that served as a sanctuary for oddballs and delinquents. Yet, he couldn't care less, as becoming a Magic Knight wasn't his goal.Everything shifted when he crossed paths with Shredica, a woman hell-bent on becoming a Magic Knight at any cost. Observing Leon's lack of ambition and his apparent detachment from the academy's pursuits, Shredica saw an opportunity. She decided to exploit him as a pawn in her ascent through the academy's hierarchy.Yet, unbeknownst to Shredica, Leon was not the complacent, unremarkable figure she presumed him to be.

There’s a legendary Bishoujo Game that has become popular among Japanese gentlemen.