There are different families and species of elves, for example those of the wild woodland, who live mainly in northern Europe. Elves are miniature reproductions of mankind, but a good deal handsomer and better made. A female elf is so extremely beautiful that a human male who glimpses her will spend the rest of his life seeking hopelessly for a maiden of equal beauty.
lf society is organised on traditional lines. They have an Elf King, whom they serve faithfully, and hereditary officials and aristocrats, but the character of each elfin community differs between one country and another. The elves of Germany are sometimes helpful to humans but occasionally malicious, so that the Germans treat them cautiously. The elves of England are full of benevolence and kindness and they like nothing better than the doing of good deeds for friendly humans.
Elves possess great wisdom, and the power of seeing into the future, but they are far from solemn in nature. They revel in festive occasions and enjoy dancing all night until the first cockcrow heralds the sun, when they vanish instantly and leave nothing but their footprints in the dew-wet grass. Men should never venture close to elves dancing in the moonlight. A mortal man who sees the supreme beauty of elf maidens dancing will be so bewitched that he must join in their circle. When the vanish at cockcrow he will disappear with them.
Elves come in many forms and appear in many cultures, but the most prominent Elven tales come from the Nordic Tradition. In that culture, there are three main sorts: Light-Elves (Sprites), Dark-Elves (Ghosts), and Swart-Elves (Dwarfs). Frey is called the greatest of the Elves, and the King of Elf-Realm. The Light-Elves (Ljusalfar) are the winged elves, or sprites (like Pixies).
The Light-Elves, which come under the rule of Frey, led by King Dain, are spirits of light and brightness, fair to see and dressed in shining colors. They inhabit the clouds directly above the earth. The Dark-Elves, (Dokkalfar, Nattalfar) are the Elves who inhabit Middle-Garth. They are the spirits of dead men who remain in some form to assist their descendants. The term "dark" refers to their shadowy appearance, NOT their nature/character. The Mound-Elves, the ghosts of dead men, are those classed as Dark-Elves. The Swart-Elves are the earthbound elves, who are also called Dwarfs and Earth Elves. They are ugly to see, but mighty and skilled craftsmen. They were made of the maggots of Ymir's slain body. Sometimes called the earth elementals. They inhabit the caves directly below the earth.