Hiisi
Hiisi (plural hiidet) is a term in Baltic-Finnic folklore, originally denoting sacred localities and later on various types of mythological entity. In Christian-influenced later folklore, they are depicted as demonic or trickster-like entities, often the autochthonous, pagan inhabitants of the land, similar in this respect to mythological giants. They are found near salient promontories, ominous crevasses, large boulders, potholes, woods, hills, and other outstanding geographical features or rough terrain. In Estonian, hiis still carries the primary meaning of a sacred grove.
The eponymous chief Hiisi is helped by a number of smaller hiidet in the Kalevala. In Poems 13-14, Lemminkäinen pursues the chief Hiisi's elk.
"Hiisi" was also one of the twelve sons of Kaleva, the great king of Kainuu in Kalevala. Those sons were later transformed into twelve constellations in the sky.
Later the original aspect of nature's awesomeness inherent in the hiidet was diminished, and they passed into folklore as purely evil spirits vaguely analogous to trolls. According to this later view, hiidet were often small in size, on some occasions gigantic. Hiidet could travel in a noisy procession, and attack people who did not give way to them. If somebody left their door open, a hiisi could come inside and steal something. If you were chased by a hiisi you should seek safety in a cultivated area. In folklore, it was the cultivated areas which were blessed in contrast to the pagan holiness residing in the awesome and forbidding features of raw nature, and evil hiisi could not step inside areas sanctified by human cultivation.
Pre-historic stone structures and large stone boulders were thought to have been erected by hiidet or giants. The Finnish term for a Bronze Age cairn grave (consisting of a pile of rocks) is a hiidenkiuas (hiisi's sauna stove). A giant's kettle is called a hiidenkirnu (literally, a hiisi's churn).
Often, the English "goblin" is translated as "hiisi" in Finnish, due to the numerous similarities between the typical goblin and hiisi. In the Finnish translations of the works of J.R.R. Tolkien, where the word "goblin" is a synonym for "Orc", hiisi is used as the translation for "goblin", whereas "orc" is translated as "örkki".
In modern Finnish, hiisi and its derivatives hitto and hittolainen are mild profanities.