The Genius Doctor, My Wife, Is Valiant - Chapter 51 - You can blame me if you want!

This is the story of Long Yi, who was killed because he took revenge for the girl he loved. Before he dies, a strange lightning carries his soul into a different realm. How will he live, when the first thing he noticed upon arrival is that, the man whose body he possessed is raping the country’s princess?

- Description from Novelupdates

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

Su Yuzhou reincarnated into the ABO world after his death and became a top-level alpha. Influenced by the conceptions of his previous life, he never thought that a susceptible period would have any effect on him – after all, as an upright young man, how could he be enticed by pheromones to push down a weak Omega?

Then, he became the one who was pushed down _(:з”∠)_

Atypical ABO story, Omega Gong X Alpha Shou.

- Description from Novelupdates

However, he did not know that he was not raising just a harmless pet, but a biological weapon secretly made by the government… a real monster.

As a former librarian, Rand felt that he had been living an ordinary life, the one that he had reclaimed unconsciously every single day.

Recently, he has been a little upset because the pet fish he accidently brought home to raised seems to have undergo some strange changes

Well, it turned into a merman.

- Description from Novelupdates