I can return to the age of mysterious - Chapter 62 - 0 Killing Intent_1

Damien reveals an ugly truth.His sister and only family, Ahara, leaves the house every midnight whilst he's asleep—a time that he soon discovers is when man-eating beasts named Rouges start hunting for prey.Unable to question her directly, he decides to investigate her and quickly figures that Ahara isn't human but rather, a vampire hero who saves them from beings like herself coming from a world she calls Gibbous—a place where entities like vampires, wizards, and beast shifters alike reside. What’s more, he also learns that the real reason behind his parents' death was the leader of the Rogues, who's rumored to have escaped after Damien’s father almost killed him.A series of fateful events lead to Damien’s long-lost power reawakening in him, and he finds himself with no choice but to return to Gibbous, a strange world where power means survival, and weakness leads to death. As such, Damien enrolls in an academy to train his newfound abilities with one thing in mind...Becoming more powerful.However, he soon discovers that the path to power is one filled with troubles and pain, and he isn’t alone in this lust for more at the academy. It’s a bloody competition against time and formidable opponents, and only those willing to sacrifice their comfort are the ones who can attain it.With a deadly foe lurking in the shadows somewhere and a strong desire to protect his sister, Damein has no choice but to fight.The only way is up, and he is going to be standing at the top of them all, ready to counter any enemy.

“Mr. Qi Lin, may I ask how you thought about joining the entertainment circle from a sports student?”

“Uh, I said that I was there to deliver lunch boxes, do you believe me?”

- Description from novelbuddy

The first time they meet, she bumps into him. The second time they meet, she agrees to a marriage contract in exchange for his help in her bid for revenge. But… he becomes addicted to loving her.

During his first attempt, he flies a helicopter domineeringly; in his second attempt, he arrogantly removes all his love rivals; in his third attempt, he tries to tie her down using a cute child. Youxuan replies with a plain resounding ‘no’ all three times.

In the end, Shan Hanjie takes one look at her, grits his teeth, and plops onto the ground. “Babe, you dropped your prince charming, please bring him home!”

This legend tells the tale of the protagonist, Kuroki summoned to protect the demon king from the hero.

Kuroki, unbeknownst to him, suddenly came to another world. He was summoned by the demon king, Modes. The territory which the demon king overrules was in the midst of being destroyed because of the hero. He had no choice but to bow before Kuroki.

“Please save us, Savior Dono!”

Kuroki nodded, deciding to save the demon king due to an unexpected turn of event.