Valkyrie are female spirits who are Odin's warriors. The Old Norse word valr, means those who fall in battle, and kyrja means to choose. In Old Norse, Valkyrie means the 'choosers of the slain', which describes their mission.
Valkyries choose the bravest and most courageous warriors to fall on a battlefield, and determine the outcome of the battle. The valkyries then take the fallen warriors with them to Asgard.
In Asgard the Norse goddess Freya gets half the fallen warriors and takes them to her home Folkvangen, "the field of the warriors". The remainder of the fallen warriors become Odin's einherjar and stay at Valhalla.
In Valhalla, the tasks of the valkyrie are to serve Odin and the einherjar. Here the valkyries ensure that the einherjar have enough mead to drink, which is an important ritual in Valhalla. The valkyries are important to sacred Norse ceremonies, and in such rituals, the valkyries fill the drinking horn with mead that brings out memories.
Valkyrie were concerned that the dead were buried in kindness, and the valkyries accompanied Odin and Frigg to one of the largest ceremonies in Norse Mythology, that of Balder's funeral.
There are two kinds of valkyrie in Norse mythology. The original valkyrie are those that come from Valhalla. The other valkyrie are half human and half divine, who lived on earth as mortal women, then traveled to Valhalla after their death.
They are also portrayed as everything from beautiful sheild-maiden/hostess to fearsome spirits. The Icelandic scholar Snorri Sturluson, between 1220 and 1241, described valkyries as semi-goddesses with shield and sword or spear. Poems and sagas written before, and after, Snorri, have described the valkyries as monsters who tread bloody battlefields in search of brave warriors.
It is written that valkyries are armed and dressed in full armor, with shields and helmets. Valkyries are skilled riders and ride their horses in herds, through the air, water and overland. When valkyries come galloping through the air can than see a glimpse of the bright light that may seem like a lightning flash across the sky. When they are on the ground, it may look like they are on fire.
Valkyries are lovers of heroes and other mortals, and some valkyrie were the daughters of kings. Sometimes valkyries can change into swans, and sometimes they have with them ravens, who they can communicate with. In the poem Oddrúnargrátr, the valkyries are also called óskmey, "wish maid", and in the Nafnaþulur they are also called Óðins meyjar, "Odin's maids".
Valkyries also have knowledge of magical abilities of the runes. They also have the power of healing and are able to give good advice on how people should live their lives. Valkyries advise on how people should behave at a Thing, Viking parliament, that a man should not argue with someone who is drunk, that he should not let a beautiful women seduce him, that he should not force young girls or married women to sex, to not be vengeful on people who have flaunted themselves, and to be brave in battle.
Some valkyries went against Odin's will, which meant that he punished them harshly. The most famous of these is the valkyrie Brynhild, whose name means 'armor battle' or 'shining battle'. Brynhild has seven sisters, all of whom are valkyries, and she is known as the strongest of the valkyries.
In the Poetic Edda is a short Old Norse verse called Helreið Brynhild, "Brynhild's journey to Hel". The poem describes Brynhild as a Valkyrie and shieldmaiden. During an important assignment for Odin, Brynhild disappointed the All-father during an important assignment. As punishment, Odin sentenced her to live life as a mortal woman.
Brynhild was imprisoned in a remote castle, where she had to sleep inside a circle of flames until a brave man came to rescue and marry her. The brave hero who rescued her was 'Sigurd the dragon slayer', and the story has a tragic ending.