Elves are mythical creatures of Germanic mythology that have survived in northern European folklore. Originally a race of minor gods of nature and fertility, they are often pictured as small, youthful-seeming men and women of great beauty living in forests and other natural places, underground, or in wells and springs. They have been imagined to be long-lived or immortal and magical powers have been attributed to them. Something associated with elves or the qualities of elves is described by the adjectives elfin, elven, elfish, or elvish. Elves are staple characters in modern fantasy. They are also called: addler (Great Britain), Alfa and Alfa-folk (Iceland), Elle (Scandinavia), Ellyll (plural: Ellyllon)(Welsh), Y Dynon Bach Têg (Welsh). In Sweden, an “älv” is a river, a word to be distinguished from “alv” (Elf), “alf” (Elf) and “älva” (female Elf or fairy). They are etymologically related.

Characteristics of mythological elves

Norse mythology

Scandinavian mythology knows of light-elves (Liosálfar) who dwell in the third space in heaven, dark-elves (Döckálfar) and black-elves (Svartalfar). The black-elves were skilled smiths and have been confused with the dwarfs of this north Germanic mythology. In general elves and dwarfs are distinguished in surviving Norse literature. The best known elven smiths are the Nibelungs, who were said to be the descendants of Ivalde, the father of Idun and Völund.

The elves (light elves) are often mentioned along with the Aesir, instead of the Vanir (a race of gods). The names Vanir and Alfar (light elves) may have been either synonymous, since the expression “Aesir and Alfar” meant “all the gods”, or designating a difference in status between the major fertility gods, the Vanir, and the minor ones, the elves. The Vanir Freyr was the lord of Alfheim, the home of the light-elves (meaning elvenhome), and he had two elves as servants, Byggvir and Beyla. Like the Vanir the elves were associated with fertility and in late fall, the “alfablot” (elven sacrifice) was celebrated by drinking beer. Milk and butter could also be sacrificed in bowl-shaped pits on flat rocks and on raised stones, which were called elven querns.

The Scandinavian elves were of human size. In Hrólf Kraki’s saga, the Danish king Helgi finds an elf-woman on an island and rapes her. Famous men could be elevated to the rank of elves after death, and in one such case, the full-sized smith hero Völund (see Weyland) is called an elf.

The dwarfs and Svartalfar live in Svartalfheim.

(from www.wordiq.com/definition/Elf)