My Shadow Monarch's System - Chapter 23: A Detour.

Everyone rumored that Z country’s young master Jun was cold-blooded, decisive, and not close to the female gender, but he took in an illiterate little girl as the pearl in the palm of his hand.

However, the little girl brought her case to the table. An illusion, it was all an illusion. What not close to the female gender? Which animal was crushing her every night?

“Baby, let me love you.” The man undressed her with his lips. She retreated pitifully, “Don’t want, don’t want, you’re bad.”

“Women love bad guys.” After eating he turned around to wipe his lips. She kneaded her pitiful little waist, tears falling, “This one is not a woman, she’s just a little mermaid.”

- Description from Novelupdates

He became a teacher at the best magic academy in the empire.
….For being mistaken for someone else.

A god of a different world had abruptly appeared in my classroom and semi-forcibly summoned the entire class to his world.ーーーーexcept for me, Kamiya Yato.

I was nothing. A lowly omega, destined to live in the shadows of stronger wolves. But on the night of my eighteenth birthday, the moon had other plans for me. My mate was an Alpha’s son. The problem? He wasn’t the only one. The Blackwood triplets—Kael, Ronan, and Darian—each bore the same mark that bound them to me.To be Luna, I would have to survive the chaos of three powerful mates, a jealous rival who wanted my place, and a secret buried deep in my bloodline.Because being chosen by the moon was never a gift. It was a curse.