Sports festival chapter pt.2, Hareta implies Misaki helped him in the past in an important way, information a player wouldn't have/care about as the game starts at the beginning of the school year. The fact that they have a shared history that both feel strongly about suggests that they're normal people within the world, as Hareta never demonstrates the detachment a player would have and seems to consider himself as restricted as the rest of them within the world, except that he's directly defying his purpose. Obviously you have to throw some logic out of the window to even accept the premise, but if Hareta existed outside of the game, it probably would have been shown by now.