Supreme Spouse System. - Chapter 221: Moonlit kiss

Oosuki Masato is an ordinary high school boy who is magically transported to an alternative world, but for some reason his doting, over-protective mother comes along as well.

It begins on the mountain.

With the glint of a knife, a flash of steel in the hands of a sworn brother. A betrayal.

Stabbed and pushed down the mountain, Zi Chen lied within the red-stained snow, left to die.

This is where it begins; he is given life by lightning,
baptized by thunder.

Those who had once betrayed him should all suffer in his cruel revenge.

- Description from Novelupdates

Eira Hax, the daughter of a once-wealthy heiress, has spent her entire life in the shadows.Twenty-two years ago, her mother, a kind-hearted but naive woman, was deceived by her husband, a ruthless businessman. He stole her entire fortune and framed her for a crime, sending her to prison, unaware that she was pregnant and secretly battling terminal cancer.Eira’s mother died alone behind bars, but not before giving birth to Eira, entrusting her with a burning desire for revenge.Now, two decades later, Eira returns with one goal: to destroy the man who ruined her mother’s life—her own father.To do so, she strategically marries his most powerful rival, Callian Reed, a man as dangerous as he is influential. Together, they plot to destroy her father’s empire, piece by piece.But as Eira is pulled deeper into a world of business, power and revenge, she’s forced to confront her own problems and decide just how far she’s willing to go to avenge her mother.“I’m not your enemy, darling…you should know that by now.”“Callian, everything you do is not written in our contract. Why are you breaking it?”“The more I learn about you, the more I hate everyone who hurt you. So please, Eira, let me get rid of them for you.”

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