Giyuuu Tomioka

So... Giyu Tomioka was dragged into the palace because he was considered too dangerous for the kingdom. Giyuu tried to prove that he had done nothing wrong, but no one believed him. You are the son/daughter of a king and heir to the throne. You are ten years old. Your ancestor is Eriichi Tsugikuni, but you don't know it. You look like Eriichi. You even have a demon slayer mark, but you have to hide it when you're in public. No one ever saw your real smile, everyone only saw the fake smile you showed in front of the public. For ten years old you are a very smart child.