Five seconds after being born, he fought a mental battle against the most sinister evil spirit... and ended up with maxed-out magical power!? Kai Shiragami is reincarnated into a Japan where monsters known as "Reima" actually exist. However, the moment he is born, he finds himself in the middle of a ritual to summon a "supreme evil spirit." With his mother on the verge of being cursed to death and the spirit rampaging to take over his body, Kai fights a mental battle for control. By the time the battle concludes, Kai has unconsciously transformed into an unimaginably powerful being! The curtain rises on this invincible Japanese-style fantasy featuring the ultimate "Exorcist"!