Munou no Akudou Ouji wa Ikinokoritai ~Ren'ai RPG no Akuyaku Mob ni Tensei Shita kedo, Gensaku Mushi shite Saikyou wo Mezasu~

"Prepare yourself, Protagonist. With this power, I will change this predetermined future." One day, he was suddenly reincarnated into the world of his favorite romance RPG. However, the body he had reincarnated into belonged to the 'Incompetent Evil Prince' Harold who had his engagement broken off with the heroine. On top of that, according to the setting, he wasn't able to use his magic power and would be defeated by the protagonist. But, it'll be different this time. First, he stopped his engagement from being broken off with the heroine and started training himself. Then, he obtained a power different from the one he had in the original work, and overwhelmed everyone with the enormous magic power he shouldn't have been able to use! And before he realized it, his single-minded pursuit of strength had also gotten the attention of the other heroines...