Elves

The elves were also called álfar. The elves were a race of mythical beings who were, in a way, lesser deities. They weren't exactly gods in the normal sense, but they did possess powers. They were similar to Roman household deities such as the Penates and Lares, where people prayed to them to protect their home and household.

People also prayed to the elves for healing, as it was the case for Kormak in the Kormaks Saga (13th century). Kormak wounded Thorvard. The witch Thordis advised Thorvard to allow the elves to heal him, so he sacrificed a bull at the elf's mound. He first slaughtered the bull, then sprinkled the blood around the mound, before preparing the meat for elves to feast on. The sacrifice was known as álfablót or "elf's sacrifice".

There are some scattered references to elves in the Poetic Edda, but their roles in Norse myths were minimal at best. Snorri Sturluson mentioned how the gods created a world for which the elves were to live in, and the difference between the light-elves (ljósálfar) and dark elves (dokkálfar) or black elves (svartálfar), but nothing about individual elves.

What we do know is that the elves or light-elves lived in one of the Nine Worlds called Alfheim. The Vanir god Freyr had his palace and hall in Alfheim, where he ruled as their god. It was said that the gods gave Alfheim to Freyr as payment for losing his tooth.

...Alfheim the gods gave to Freyr
in bygone days as tooth-payments.

Grimnir's Sayings 5, from The Poetic Edda
translated by Carolyne Larrington

There were other types of light-elves such as muntælfen (mountain elf), landælf (field elf), wæterælfen or saeælfen (water nymph) and wuduælfen (wood spirit).

There were several different types of elves, and they seemed to be related to the dwarves because Snorri referred to the black elves (svartálfar) as dwarves, or the black elves are not elves at all. The black elves lived in a different world called Svartalfheim, while the dwarves lived in Nidavellir.

As to the dark elves (dokkálfar), Snorri said that they were blacker than pitch and lived underground. They are unlike the light-elves in appearance and nature.

I should also mentioned that in the Eddaic poem titled Volundarkvida – the "Lay of Volund" – the master smith Volund (Wayland) was known as the Lord of Elves. Which type of elves did he belong to? Or was he really the lord of dwarves, who were known as black elves (svartálfar)? Since Volund/Wayland was a master craftsman/smith, a skill often attributed to the dwarves, then Volund could very well be the Lord of the Svartálfar. Volund was popularly known in English speaking countries as Wayland.

The truth is that the writers in the Norse myths didn't have much to say about the elves. Their roles were developed more later in folklore, fairy tales and in the world of fantasy novels, such as by the novelist J. R. R. Tolkien's The Lord of the Rings.