Kobolds are a fictional sapient species originating in German folklore.
Earliest accounts of kobolds describe them as "sprites" who can incarnate themselves in various forms, be they animal or human. Some such kobolds are known as 'drakes' or 'draches'; they are fiery spirits able to fly through the air and enter a human home through its chimney. The later, more well-known version of the kobold resembles a Goblin in appearance, being a small and ugly humanoid.
Of these kobolds, there are three types. The first one, or household kobold, is identical in behavior to a brownie, executing various chores for the family in exchange for food and shelter. Another type of kobold looks older lives in mines (similar to classic dwarves and Scandinavian trolls); these were often depicted as malicious and responsible for mining accident, possibly out of jealousy for the human miners' findings. Finally, sea kobolds, also known as Klabautermen, helped sailors in a manner similar to household kobolds for normal folk.