Kobold

Kobolds are among the oldest attested Germanic spirits, appearing in medieval German literature as household spirits closely analogous to the Scandinavian nisse. A kobold would enter a home of its own choosing and attach itself permanently. Some kobolds haunted mines (Berggeist) where they led miners astray or warned them of danger. The word 'cobalt' derives from the miners' belief that kobolds had poisoned the ore.

Appears as a small humanoid, sometimes like a child, sometimes an old man, often in nondescript clothing. Mine kobolds might look like small miners. They preferred to stay invisible and were primarily detected by sounds — tapping, footsteps, laughter.

Household kobolds helped with chores, warned of danger, and brought prosperity. Mine kobolds could lead miners to rich veins or cause cave-ins. When angered, a kobold could sour milk, hide tools, trip people, start fires, and refuse to leave.