Vttir (Old Norse; singular Vttr) or wights are nature spirits in the Norse religion. These nature spirits divide up into ‘families’, including the lfar (elves), Dvergar (dwarves), Jtnar (giants), and even gods, the sir and Vanir, who are understood to be prominent families among them. The term ‘families’ (ttir) is often translated as ‘clans’ or ‘races’. These families sometimes intermarried with each other, and sometimes with humans.

Sjvttir (sea spirits) are guardians of the specific waters. The tomte or nisse is a solitary vtte, living on the farmstead. He is usually benevolent and helpful, which can not be said about a mischievous illvtte. However he can cause a lot of damage if he is angry, such as killing livestock. The Old Norse term vttir and its English cognate wights literally mean ‘beings’ and relate etymologically to other forms of the verb to be, like was and were. Vttir and wights normally refer to supernatural ‘beings’, especially landvttir (land spirits), but can refer to any creature. The Norwegian vetter is used much in the same way as the Old Norse vttir, whereas the corresponding word in Swedish or Danish is vsen or vsen (being), also akin to was and were.

In the Late Viking Age, Nordic kingdoms began converting to Christianity. Non-biblical Christian concepts of nature spirits, especially the German conflation of dwarves and elves and French concept fairyfolk (Old French fae), increasingly influenced the Norse concept of nature spirits. Generally speaking, from about the 13th-century onward, the Norse Vttir shrank in size. A titanic Jtunn diminutizes into a large Troll, and a human-sized lfr into fairy-like knee-high Nisse. While the Trollir tend to represent the spirits of wild locales and the Nisser the spirits of human settlements, they overlap greatly. Both groups acquire traits of earlier Dvergar.

Landvttir (land spirits) are chthonic guardians of specific grounds, such as wild places or farms. When Norse seafarers approached land, they reportedly removed their carved dragon heads from the bows of their longships, so as not to frighten and thus provoke the landvttir to attack, thereby incur bad luck from them. Icelandic culture continues to celebrate the supernatural protection over the island, and four landvttr can still be seen in the Icelandic coat-of-arms: a troll-bull, troll-eagle, dragon, and handsome giant. The troll-animals are actually Jtnar who shapeshifted into the form (and mentality) of an animal, and such animals are supernaturally strong. Even the dragon is generally a troll-snake: compare the Jtunn Loki whose children include a wolf, a serpent, and a horse.