MTL - Fairy Tale - Chapter 295 found it

He, since childhood, had followed the Foreigner to practice the Defying Heaven Art, entering the most secretive special forces and becoming a fearsome assassin that made others tremble at the mere mention of his name. After a single failure, he took early retirement, but he ended up as the personal bodyguard for a rich heiress, a school beauty. Accidentally provoking some mysterious Cultivators, he gradually unveiled a hidden world of Cultivation beyond the mortal realm...

The notorious imperial court lackey and the meritorious military general were well-known for their mutual dislike, a pair of arch-enemies set in stone. Who could have foreseen the unexpected change in the winds of heaven: the general injured on the battlefield, both legs disabled, and even forced by the emperor to marry his nemesis.  

With one marriage edict, two people with mutual hostility are forced to marry and live under the same roof. Yet after these long days together, they come to the realization that this fellow is not truly devoid of any saving grace/unattainable and high out of reach.

- Description from Novelupdates

In a world of wizards and witches, Jaegar undergoes reincarnation and enters a mysterious realm. Driven by a desire for pleasure, he embarks on a journey of self-discovery, encountering challenges and uncovering secrets along the way. As he explores the magical arts, Jaegar's pursuit of pleasure shapes his choices and drives him forward, leading to both fulfilment and consequences. This is a story of a young man's quest for pleasure in a new and enchanting world of wizards and magic.

Entered the academy in the game.

With unbalancing skills that destroy the balance of the game’s original storyline.