They are short, apparently ugly and shy. Probably shy because of how people perceived them. They are nocturnal creatures never appearing during the daytime and they would enter households when the inhabitants are sleeping. Then they would come into houses just to keep warm and sit near the fire.
They are said to be invisible except to certain people with a gift to see them. Normal people could only see them when they are touching those that has the power to see them. Also, they have a thing for musicians, often kidnapping or luring them into their dens and then asked to perform.