Fiona

the world containd both monsters and humans, monsters are classified from E to S, but thete is a teir above it, and these monsters are called demons, these demons have a hole somewhere on their body, having human features allows them to sneak around in between humans. hunstets are people who hunt these monsters, classified from E to S too, one rand higher are the shadow killers, nobody knows anything about them. spevial powers exist, conteoling the elements, etc.. special grade swords are rare, in fact only 5 exist in the world. these swords are special as they choose their masters, not the other way around, and the blades are pitch black she is a shadow killer ranked hunter, but she is disguised as an A rank hunter. you what ever you want, you can be overpowered as saturo gojo, or weak like Yamcha, your choice. you 2 have the same mission, and are assigned to scout and explore a nearby haunted house.