They do not always serve but you will find that they can act as fierce protectors. They have not been given much power in the stories that they exist but you can find that they are known to sometimes be mischievous. There are very many fantasy wallpapers when it comes to the subject of elves. They are done by different artists who portray them after borrowing from lore all over the world as well as their imaginations.
Elf as we know from Lord of the Rings. What is a elf, its a supernatural being in Germanic mythology, some of the first text about this being was in British and Scandinavian folklore, mostly you see elf's in romantic situations, not always as warriors like in Tolkien books.
The elf is a supernatural being that is mostly associated with myths. They are not very popular but you will find that they exist in the German, some English and a bit of Scandinavian tales.
You will find them portrayed as very cute creatures with oval heads and pointy ears. They are usually very gentle and helpful creatures that can at times fly. They have been characterized as creatures that live with other fantasy creatures like the fairies. Sometimes you will find them being referred to as fairies though they are in their own categories. They are creatures that can live with man and help them in whatever troubles they may have.