A type of spirit discovered by a researched named Kuroi on the new continent. Called "Kuroinyan" from its discoverer's name and because it seems "catlike". Their young look like black cats, but as they mature, they gradually come to look like beast people.

They like people, so they're easy to catch. They're obedient and easy to raise, so they're suitable for pets and familiars. Although they are quite intelligent, they don't make noise or speak. With sufficient familiarity, mutual understanding is possible.

They can apparently grow up even more with enough work.