This action-fantasy isekai follows a protagonist who is reincarnated as a "mob" (a background NPC) in the world of a video game he once played. Despite his desire to stay out of the spotlight and live a peaceful life, his overwhelming strength and "berserker" tendencies lead him to accidentally derail the game's original plot. The Berserker NPC Unknowingly Destroys the Main Story
The Eminence in Shadow or search 無自覚チート漫画 on your favorite manga aggregator. This action-fantasy isekai follows a protagonist who is
"-Manga Kyou: Senshina Mob Mujikaku ni Honpen wo Hakai Suru Manga-" — An Analysis of Genre, Theme, and Narrative Subversion and Narrative Subversion