A Cat Sith, Cait Sith or Cat Sidhe is a large elven cat as big as a dog. They are black with a white half-moon on their chest.

All cat sith are intelligent beings with their own language and many of them also speak the common language of their area, which is often the Elven tongue. Some of them have been known to live in a house where there is no children, where they don’t consider themselves to be pets but rather advisers.

They refrain from battle against stronger creatures. They can always move without sound and have the ability to become invisible at will, entirely or partially. They are as long-lived as elves.