Ayakashi Defense Force.

In a world where some humans can see Ayakashi and often interact with them there are those who form contracts with Ayakashi to turn them into weapons to fight off Phantoms and Phenoms that hunt especially Ayakashi to eat but also humans.

One such pair is a human boy called Shuro Kitsuro and a humanoid feline Ayakashi called Rena, they meet when he is just a kid.

Follow their story along with other members of the "Ayakashi Defense Force" as they face threats like Phantoms and Phenoms.