Strangeness Is Coming: Don't Believe That You Are the Protagonist!

Don't believe you are the protagonist! Never believe that you are the protagonist! Don't... Don't... Strangeness has descended on the world, and everyone is forced to participate in various dungeons. The first words they hear are "Don't believe that you are the protagonist!" When someone discovers that they have everything going smoothly or that they have narrowly escaped death and have passed the strange dungeon and "think they are the protagonist", the next dungeon will not only lead to death! And he died miserably! People also started to brainwash themselves, but in the end, it seemed... It didn't work... Because from the beginning, it seemed... It seemed like a game...