After being left for dead, Denji turns into a devil-human hybrid with chainsaw powers, and gets recruited into a governmental devil hunting agency.

In an unexpected turn of events, dull high school student Hiro Yuuki obtains the full dive role-playing game Kiwame Quest. Created by the best of technology, the game claims to take "reality to its extremes," from stunning graphics, NPCs' behavior, to the scent of vegetation, and even the sensation of wind brushing against the skin—everything was the result of an ultimate workmanship. Except, the game is a little too realistic and messy to clear. Kiwame Quest features over ten quadrillion flags and reflects the players' real-life physical abilities in the game. Being hit in the game also hurts in real life and slash wounds take days to heal. The only reward here is the sense of accomplishment. Conquer the most stressful game in history that can't be played casually!