Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 1 - 1-8. The Demon, the Knight and the Magician

Kusumi Chiharu gets a message one day that he has been selected as a Monster Tamer, and he is prompted to select his first partner. He thinks little of the message until he receives a giant package the following day. He assumes it’s the porn books he ordered, but the huge box ends up containing the unconscious body of a near-naked girl! She’s a ghoul named Zonmi, who intends to fight beside him as his partner.

However, it turns out that other hot girls at his mostly-male high school are also magical entities, and Zonmi may not be the only one who wants to fight by his side!

“She is the one who forced me to marry her, she is also the one who pushed away ShuangAi from me, she threatened my family with her family power and all these years, she did everything to subdue me...that evil woman MuTan“

If I fail to seduce all the heroines of this s*xy game, I’ll die.

“Xiao Chen, please give us another chance!”Xiao Chen stared at them with a loathing gaze. “Ten years ago, you looked down on me. You showed up at my doorstep, forcing me to break off the engagement. My dad was so enraged that he was hospitalized. Now you're actually here to beg me?”It started off as an ordinary decline of a rich family. However, to everyone's surprise, the insignificant Xiao family actually gave birth to a bigwig who was powerful in the politics, military and business world. Just when all the major families could not stand the pressure brought forth by Xiao Chen and were forced to apologize, they discovered that he had disappeared!At the same time, in a small family of a small town-Xiao Chen exclaimed, “Mother-in-law! I am really here to repay your daughter's kindness. There's nothing else between us!”In order to pay back his debt of gratitude, Xiao Chen hid his identity and came to this small town. But his mother-in-law treated him in a totally unexpected way!