The story takes place in the Mogle, a land filled with “monsters” and people with the illest of intent. Because of the concentration of evil, demons are able to escape hell and enter onto the plane of Earth. To solve this problem, the Ancient Ones created Irven, Tasha and Wrigley, angels assigned to do whatever it takes to keep demons in hell.
Irven is assigned to protecting the Mogle from demons, and while engaged in a battle with Clover, the demon of trickery and luck, he accidently releases multiple demons from hell and accidently kills an unnamed resident of a local village. Irven attempts to kill as many demons as he can, but many get away and thus, our story begins.
When the person was killed, the Ancient Ones decided that he was unfit to enter heaven nor hell because he did nothing wrong. Therefore, using the souls of the demons killed, Vortino is given life as long as he bows to slay every single demon that escaped hell. Vortino agrees, and him and Irven, despite being pretty mad at each other ( Vortino because Irven killed him, and Irven because he doesn’t like anybody ) are tasked with tracking down each demon and sending them back to hell.