This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Kobold (German)
Although usually invisible, a kobold can materialize in the form of a non-human animal, a fire, a human, and a candle. The most common depictions of kobolds show them as humanlike figures the size of small children. Kobolds who live in human homes wear the clothing of peasants; those who live in mines are hunched and ugly and some can materialise into a brick.
Kobolds who live on ships smoke pipes and wear sailor clothing. Some kobolds have been called the spirits of caves and mines. Still others have specific names, such as Hodeken, who frightens unfaithful wives, and Goldemar, who sees the secret sins of the clergy.