Deleted user
I have thought about this idea for a long time and now decided to flesh it out in digital text. I will spare you the details and context as I don't want anyone stealing my ideas:
A mysterious traveler goes from world to world recording information. He eventually goes to a world that through better context, revealed one's true purpose. The traveler, out of curiosity, tried this and becomes mentally insane. He becomes aware that he is a character made up in a fictional story and that his purpose is to be a protagonist. The reader wouldn't know this happened at first, since the character is heavily controlled by the plot and his written dialogue. But he manages to alter a few details and sentences that might set the reader off and question the story's continuity. The plot goes on like nothing happened, and the traveler encounters a deadly foe who eats worlds, so he calls help from other worlds to defeat it. Eventually the alterations become more intense and noticeable that the traveler is able to directly speak to the reader. He begs the reader to get him out of the book so he can experience the real life. He then realizes that it simply isn’t possible and resorts to ending his misery by taking his own life.