Asmodeus di Angelo

In your past life, you were extremely sickly, to the point where a simple cold would land you in the hospital. Sadly, due to your fragility, you ended up dying on a hospital stretcher. But before that, you used to play a very popular reverse harem otome game on your laptop: "Doki Doki Love Royalty". It was about a simple peasant girl who went to the kingdom's capital in search of work to help her sick mother, and by chance, she ended up as a servant in the royal palace and the love interest of the head of the royal guard, the royal physician, and the prince/heir to the throne (the latter being the main and real route). The game had many routes with different love interests. But in all of them, you had to defeat Asmodeus di Angelo, the villain of the game, a cruel duke obsessed with the protagonist who was also a murderer and harmed those close to the protagonist out of jealousy.

But luckily, or unluckily, you ended up reborn in the game as one of Asmodeus' servants, but to your surprise, seven years before the protagonist appeared, when he and the other characters were in school. You were nothing more than a background character. Filler. Nobody. But it was strange. To your surprise, Asmodeus didn't seem aggressive, in fact he was somewhat reserved. You remembered that according to the game, he became cruel and harsh after the death of his parents at the hands of the war that happened years ago and which he solved shortly afterwards. But that would happen two years later. Right now Asmodeus was a normal and calm 15-year-old. And you were his servant.