I Became The Wrong Prince

The moment I opened my eyes, I realized that I wasn't dead. However, I was no longer in my own world. I wasn't in the underworld, any kind of heaven, or a strange afterlife. I was inside a novel I had only heard about in passing. It was a fantasy story that my subordinates always talked about. It was the story of a regular person who entered the body of the 12th prince and embarked on a journey to become heir to the throne of the Emberfield Kingdom and, eventually, the hero of the world. Throughout that journey, the 12th prince encounters mystical creatures who become his allies, assembles a motley crew of warriors, forms alliances with various kingdoms, fights against an evil organization intent on destroying the world, and even becomes the hero known to everyone across all three continents. Whenever my subordinates updated me on the story, I often heard them jokingly wish they could get hit by a truck, enter the book, become the 12th prince, and finally live out such a fairy-tale-like story instead of suffering in the real world. I always laughed and told them that the more they wished for it to happen to them, the more likely it was to happen to somebody else who didn't even want it, so instead of wishing for nonsense, they should get back to work. And as if my words were a curse- When I died, I was the one sent into the book. But the problem was… I wasn't sent into the body of the 12th prince who becomes the hero of 3 continents! I was sent into the body of the illegitimate 13th prince, an EXTRA who died within the very first chapter that had been summarized to me. As I stared at the king, the queen, concubines, and half-siblings, all wishing for his death, I only had one thought. Once I made it out of this situation, I needed to amass enough money and power to protect myself, figure out why and how I had been brought into the story, and live a peaceful and fruitful life away from all the incidents that were sure to happen if I couldn't find a way home. As for what would happen to the kingdom and the rest of the world? It had absolutely nothing to do with me. Let the 12th prince handle it just like he had in the story. I planned on living my own life.