As cities and towns expanded, supernatural beings learned to disguise themselves in human form. Sometimes they eat a human and cause a fuss in the news about supernatural incidents, but most of the time they lay low. So stories of evil youkai became extinct, and it is no longer necessary for celestial patrols. Earthly youkai know how to blend in, but sometimes there are troublemakers. Some celestial beings descend to the human realm, attracted by earthly temptations. And so the heavenly court must send spirit agents to capture and discipline them, before they cause too much damage…