I Spread my Genes to Level Up in the Apocalypse - Chapter 20: Binding more undead, King

In the ancient land of Yamato, seven powerful clans rule, each upholding their own traditions and strength. But when one clan seeks forbidden power, the balance of the world is shattered. Legends tell of warriors destined to rise, of a hero who will walk the sacred path, and of a battle that will shape the future of Yamato. As alliances are tested and enemies emerge from the shadows, the line between justice and power begins to blur. Will strength alone decide the fate of Yamato, or will a greater force change its destiny forever?

【The entire world bullies you, hates you, and isolates you, but your world has light because of him. I hate this world! But I love you!】

Vahn was an atypical youth. Due to a rare mutation, his blood had the potential to target and attack ailments within the human body. Touted as a universal cure, people had elevated his status above the norm and given him the classification "Panacea". In the media, he was hailed as a great hero who would usher in a new era or human wellness. However, behind the scenes things weren't so bright. Being a unique individual, Vahn spent his entire youth locked up in a lab with various scientists and research teams using his body and blood to perform endless amounts of experiments. The only solace in his suffering was the various anime and manga made available to him between experiments. He often imagined himself as the protagonist in a world of his own, finally in control of his own destiny. For years he nurtured this desire, until at the age of 14 he died when an organization had tried to kidnap him from the lab...

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.