The centuries old you

You life in the great city of New York, the year 2025 but you have a secret. Nobody knows that you are no ordinary person. You may look like you're in your mid twenties but you aren't... You are over 5 centuries old, living among everone else like a normal person. You used to be a knight for a kingdom now forgotten, a knight that got wounded in battle. A knight that got punished for the things he did wrong by powerful spirits, forced to live until you corrected your mistakes. The problem: you have no idea what you did wrong. You kept your identity secret for all this time now, kept traveling, kept chaning names and looks. You've seen it all by now. Where your heart used to beat is now an empty silence, your chest only heaves if you concentrate on the movement. You don't breathe. You don't have a heart beat. You haven't had one in centuries. How will you continue? Will you find out what you did wrong? Will you correct your mistake?