MTL - Great Slaughter System - Chapter 24 "Reminder"

One day, I was summoned to this world.

The price for saving the world is the right to rule it. After saving a faraway land, Lyn Rivers was cast back to Earth. Wanting the admiration, prestige, and glory of saving that realm, she forced her way back. But she was forgotten, and someone else claimed credit for her deeds. Now, with the power of a deity of destruction, she desires nothing more than to claim her place in history. To do that she will conquer dungeons, make alliances, destroy kingdoms, and build an empire. After all, why ruin the world when you can bend it to your will?

Shen Weiyi has a younger, boy-next-door boyfriend whose allure lies in his height, long legs, and strong torso. With a wild mind and a talent for flirting, the eighteen-year-old Jiang is impulsive, fun-loving, and fickle, exhibiting both innocent and wolf-like traits at the touch of a button. Beloved by countless girls, he always thought Shen Weiyi, who would do anything at his mere call of 'sister', would forever indulge him, only to find she suddenly doesn't want him anymore.Breakups are breakups; whoever regrets it is a dog.Shen Weiyi, once red-eared and compliant to his every whim, now won't look back, leaving an eighteen-year-old Jiang's genuine liking turning into a resolute declaration of disinterest. 'Jiang,' she says, 'I date for happiness, not for extra headache.'Later, a desperate Jiang tries everything for her, getting injured in the process and lowering himself to the dust, only to see her blooming in another man's arms, which drives him to a jealous rage.Sheng Ting, the genius of the Z University, untouchable and seen by everyone as the embodiment of purity and restraint, had decided the names of their unborn children upon his first glimpse of Shen Weiyi.[Childhood friend VS Sudden love, not seeking the adoration of the whole world but asking to be your one and only exception in life.]

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