King Goldemar or King Vollmar is a famous kobold in Germanic folklore.
Legend
King Goldemar lived in great intimacy with Neveling von Hardenberg, on the Hardenstein at the Ruhr, and often slept in the same bed with him. He played most beautifully on the harp, and he was in the habit of staking great sums of money at dice.
He used to call Neveling brother-in-law, and often gave him warning of various things. He talked with all kinds of people, and used to make the clergy blush by discovering their secret transgressions. His hands were thin like those of a frog, cold and soft to the feel; he let himself be felt, but no one could see him. After remaining there for three years, he went away without offending any one. Some call him King Vollmar, and the chamber in which he lived is still said to be called Vollmar’s Chamber.
He insisted on having a place at the table for himself, and a stall in the stable for his horse; the food, the hay, and the oats were consumed, but of man or horse nothing more than the shadow ever was seen. When one time a curious person had strewed ashes and tares in his way to make him fall, that his foot-prints might be seen, he came behind him as he was lighting the fire and hewed him to pieces, which he put on the spit and roasted, and he began to boil the head and legs.
As soon as the meat was ready it was brought to Vollmar’s chamber, and people heard great cries of joy as it was consumed. After this there was no trace of King Vollmar; but over the door of his chamber was found written, that in future the house would be as unfortunate as it had hitherto been fortunate; the scattered property would not be brought together again till the time when three Hardenbergs of Hardenstein should be living at the same time.
The spit and the roast meat were preserved for a long time; but they disappeared in the Lorrain war in 1651. The pot still remains built into the wall of the kitchen.
Source
THE FAIRY MYTHOLOGY BY THOMAS KEIGHTLEY (1850)