I Possessed a Different Genre?

Ian, who was peacefully sleeping in his room, suddenly finds himself transmigrated into a novel. When he opens his eyes, he realizes he's not Melissa, his sister's favorite character and a notorious villainess... but rather, he's transmigrated into Melissa's older brother, who has been unconscious for the past three years. "Doctor! My brother has woken up. Quickly, summon the doctor!" Melissa, who is too kind to be called a vicious villainess. The reason Melissa became a villainess was because of her fiancé and the male lead, Adrian. There's no way I'm giving my sister to a guy like you. For the sake of Melissa's happiness, who is his sister's favorite, Ian aims to break off their eng...