Youkoso Jitsuryoku Shijou Shugi no Kyoushitsu e - Volume 15.5, Chapter 4: The Growth in Each of Us, Part 5

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.

Summary Version 1:

The mysterious boy Ling Chen is saved by a little girl as he lay on the street dying. Years later, he strikes a deal to save this savior-turned sister and enters the virtual world. In a future Earth where advanced warfare has forced nations to settle issues virtually or else suffer the consequences, Ling Chen bursts into the scene and goes from unknown to legend. Yet all is not as it seems, for Ling Chen has a dark past, and there is a greater mystery at hand behind this virtual world.

Summary Version 2:

To save his terminally ill little sister, Ling Chen enters the newly released virtual game world and joins a small gaming studio comprising entirely of women. From now on walking upon his path towards the pinnacle. An ancient, evil item almost forgotten by history, the “Lunar Scourge” helps forge his unsurpassable legend, and causes him to unknowingly step upon a path that is destined to be punished by the heavens, the way of the shura.

Using the ability to freely travel between Earth and the fantasy world so he can… become a porter of two worlds…?

Bai Yang’s objective was to establish a production line that would yield hundreds of millions of pills, pellets, and artifacts…

- Description from Novelupdates