Omega Summoner - Chapter 2453: The Sins Rebellion

She was originally an assassin. After rebirth, she was reduced to another world’s Di family’s most inferior concubine-born daughter. With an extremely hideous appearance and no way to cultivate, she was the object of everyone’s humiliation and bullying.

Kōdo Ikusei Senior High School, a leading prestigious school with state-of-the-art facilities where nearly 100% of students go on to university or find employment. The students there have the freedom to wear any hairstyle and bring any personal effects they desire. Kōdo Ikusei is a paradise-like school, but the truth is that only the most superior of students receive favorable treatment.

The protagonist Kiyotaka Ayanokōji is a student of D-class, which is where the school dumps its “inferior” students in order to ridicule them. For a certain reason, Kiyotaka was careless on his entrance examination, and was put in D-class. After meeting Suzune Horikita and Kikyō Kushida, two other students in his class, Kiyotaka’s situation begins to change.

When an S-class elite assassin-raised captain of a special ops suicide squad comes home from a high-stakes Africa mission, he finds himself offered something that could potentially set him up for life- a curious assignment that he could use to finally exit his days of war and slaughter.

Then placed into a high-school setting, Lin Yi is tasked by the chairman of a top-tier multi-billion company with bodyguard duty for non-other than his own daughter, a certain little Miss of said high-school.

His enemies, once ranging from drug lords, mafia bosses, political figures, and national leaders, are soon replaced with spoiled kids who happen to have rich papas and mamas, and Lin Yi finds his intense expertise and high-threat skillset misused, and very underwhelmed…

But he does get a harem cast as diverse as his old enemies, so Lin Yi decides that, for the sake of messing around with girls as an invincible entity in a down-leveled environment, leaving his bloody and death-filled war days behind is something he’d definitely want to strive for.

- Description from Novelupdates

Ajax used to coast through life before his parents died, after that he focused hard to try get his life back on track but that wasn't really happening and it all ended the day he got mugged. Given a second chance at life he now looks to become someone who matters and is willing to work hard from the beginning to make that happen.