While the main game does not make it clear, other material, including the official Persona 3 Club Book, reveals that Nyx is an alien that is known as the Planet Eater. There are also hints to this in some of Elizabeth’s story cutscenes in the Persona 4 Arena games.he first time or the first time in a long time, I’ve created a previous Persona 3 boss guide for every single one that you fight.