Global Reincarnation: Only I Know the Plot - Chapter 931:

When the eldest prince Luo Fei reached 18 years old, the database automatically screened the genes of omegas across the entire empire for matching. The only son of a wealthy businessman, Mo Lin, had a gene match of more than 90% with the eldest prince. However, the moment he saw Mo Lin, Luo Fei learned that this omega is a sick child with paralyzed legs, hemiplegia, and severe mental illness???

Year 2099, the world as we know it now advanced in technology. Learning has become easier, and so is transportation. But in this new advanced world there is undoubtedly problems, beings who want to use the new technology to bring chaos and strife to humanity. Xander, a 17 year old normal High school boy buys a new MMORPG game and through it, he improves his skills in all aspects. He lived a normal life until one day when his father, who abandoned him and his mother for a year came back, claiming to be the leader of a group of super humans. This was the day Xander’s life changed. He was told he will get a power to stop the enemy but what will it be? Is he even ready to take on such a responsibility? Nobody knew that this enemy group were in charge of G. CO, the creators of League of Guardians virtual MMORPG game. What they plan to use the game to accomplish was... absurd... but anyway, read to find out. Let’s Follow Xander on his journey as he becomes the strongest Super human and save humanity from doom. ... [You have killed level 51 reaper] [Do you wish to demonify, level 51 reaper?] “Yes.” [You have created a new demon, Lich] The ability to create demons from dead creatures. With this power he shall defeat his enemies and get his peaceful life back.

It’s a story about a man who got transported into a novel and possessed a slum boy. He met a noble girl and served her as a butler for 13 Years. Now the girl has already fallen from her noble life and lives in an abandoned mansion with paralyzed legs. Why did she become like that? Of course because she is the villainess in the novel.