From German mythology, a Kobold is…well is just whatever it wants to be, or needs to be. It can also be invisible.
Originally from Gask, Lilian (1865-) The Fairies and the Christmas Child. Illustrated by Willy Pogány (1882-1955). London: Harrap & Co., and New York: T.Y. Crowell (n.d. [First published 1912 in both countries])
It’s most common forms are fire, a human, an animal or a candle. They are, in essence, spirits.
There are different breeds of Kobolds. There are the ones that live on land in people’s homes. They dress like peasants and are very helpful around the house. In the old days and on farms they would milk the cows, gather eggs, carry water. If they weren’t fed on time they would become rather malicious and play tricks on the people they served.
The kobolds who live in the mines are said to haunt them.They are ugly creatures, bent over and ghastly looking.
Sailors are not without their own Kobolds, who puff on pipes and dress for the sea.
Johann Wolfgang von Goethe’s Faust…
Who doth ignore The primal Four, Nor knows aright Their use and might, O’er spirits will he Ne’er master be.