Dark Cat

Dark Cat is an OVA produced by the Nikkatsu Corporation. Inside every human soul is both good and evil. Two spiritual cats, Hyoi and Ryoi, travel across Japan trying to contain the outbreak of evil energy. During their search they run into Aimi, a depressed girl with a one sided infatuation with a classmate. Eventually her depression awakens the evil in her classmates, transforming all of them into an amorphous cancerous blob. Aimi's unrequented love is able to reach her, and by returning her light he saves her, and the two float up to heaven.