From Studio Ironcat:

A vampire with the blood of the otherworldly Shinma running in her veins, Miyu has kept humans safe from the ravenous appetites if the evil Shinma for many years. With her faithful companion, Larva, she has banished more Shinma to the darkness than humans can remember. Now a new evil threatens Japan. Western Shinma have set their demonic sights on conquering the spirit world of Miyu's homeland. The masked sorceress Carlua, has come across the sea after Japan's spirit, but why is she so enamored with Miyu's beloved Larva?