The supporting character's harem is very normal - Chapter 142 Lathel and Charlotte.

She killed his wife, destroyed his reputation, and ran off with his son. 8 years later, she returned home with her genius son, who already had a fiancée. “Give me the child, or you can’t afford the price.”“A girl who eats meat and vegetables doesn’t suffer, if you want a child, find yourself a woman to give you one.”

Han Yang never thought he would one day sell himself into a marriage with another man. He believed his life would be mundane but that man, named HeLian Qing, broke his pre-planned life. Parental debt, a child’s compensation, he had no chance whatsoever to resist, he has no ability to resist.

Shen Dongqing is a powerful, thousand-year-old ghost. He had just possessed a body and hadn’t even relaxed for two days yet when he was pulled into a white, parallel world.

On the first day of the Infinite Nightmare Game:
Other players tremble, crying and wailing wanting to go home.
Shen Dongqing eats, sleeps, and plays ‘Fight the Landlord’ (card game).

The second day:
Other players are chased endlessly by ghosts, crying loudly ‘Save me!’
Shen Dongqing eats, sleeps, and plays ‘Fight the Landlord’.

The third day.
Shen Dongqing……
The ghosts finally set their sights on this lazy player. The other players watch on in glee. As a result, who knew that this slim and pale youth would stand up and easily dispatched the ghosts with his bare hands.

Other ghosts: Can’t afford to disrupt this elder. Let’s go, let’s go.

- Description from Novelupdates

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