Manga Kyou Senshina Mob Mujikaku Ni Honpen Wo Hakai Suru Manga Extra Quality Instant

With the Main Story destroyed, the "Final Boss" arrives early—the Demon Lord Valthor, tired of waiting. He comes not to fight, but to beg Gale to stop breaking the game mechanics.

The series Kyou Senshina Mob, Mujikaku ni Honpen wo Hakai Suru (translated as The Mad Mob Character Unknowingly Destroys the Main Story ) is a Seinen Isekai manga written and illustrated by Satou Ryousuke With the Main Story destroyed, the "Final Boss"