Tales about Kobolds imply the existence of Monobolds

Let's ask the source of all earthly wisdom:

Legends tell of three major types of kobolds. Most commonly, the creatures are household spirits of ambivalent nature; while they sometimes perform domestic chores, they play malicious tricks if insulted or neglected. Famous kobolds of this type include King Goldemar, Heinzelmann, and Hödekin. In some regions, kobolds are known by local names, such as the Galgenmännlein of southern Germany and the Heinzelmännchen of Cologne. Another type of kobold haunts underground places, such as mines. A third kind of kobold, the Klabautermann, lives aboard ships and helps sailors.

https://en.wikipedia.org/wiki/Kobold