My Slayer System: Rise to Supremacy - Chapter 14: A New Technique

Xia Zhijun got the title ‘study god’ after scoring first place in the whole city. He’s the model of a good student in a teacher’s eyes: good grades, good manners, and quiet. When he wasn’t smiling, his entire body emits a cold abstinence aura. The girls only have the guts to look from afar and not get close.
Later, it was rumored throughout the entire school that even the study god would fight and hit on girls. Whoever dared to provoke his girl, he would teach you how to be a person at every minute. The night of the graduation ceremony someone saw him blocking Gu Siyi in the corner. He didn’t stop kissing even when she cried. He bit her lips and said in a raspy voice, “I’m going crazy…”
During college finals, Gu Siyi almost bursted out crying, “I’m such a failure. I won’t be able to find a good job in the future…And if I can’t find a good job, I can’t provide for myself…”
Xia Zhijun played with her pink earlobe and remarked, “I’ll take care of you.”
After they graduated, Xia Zhijun created a research company and Gu Siyi became the boss’s wife.
The commercial rocket, “Star of Siyi” was successfully launched. So everyone knew that the new technology superstar, Xia Zhijun has a wife who he spoils a lot.

- Description from Novelupdates

Nicole d'Armand never expected to walk into her apartment and find her fiancé *bleep*-deep in another woman's lady bits. What's a girl to do?Well, after obliterating an 18th-century Meissen vase, delivering a punch that would make a heavyweight boxer proud, and embarking on a night of raucous drinking, Nicole figures she might as well embrace the chaos.But when alcohol and pheromones collide, her wild night spins into something unexpected... Like a ride on the Logan Everett express.Which, naturally, leads to a whirlwind of its own: She's his fated mate. Because of course she is.And he rejects her. Because of course he does.Now embroiled in a mystery bigger than her post-breakup hangover, Nicole finds herself the prime suspect in a murder she didn't commit—no matter how tempting the thought might have been. And the only person who believes her innocence? The same guy who shot down the idea of being her fated mate.Great. Just what she needed: her love life is a crime scene, and the man stupid enough to let her go is holding her freedom in his hands.

Karl Adelheit, a self-proclaimed ordinary student returning from military service.

And a nobleman who enlisted as a soldier and received Medals of Honor.