They apportion victory in battle according to Odinn's commands, and scour the battlefields for those who are particularly brave, or show particular skill in the arts of combat. The bravest warrior was he who ran head and heart first into the violence, seeking to conquer an opponent not in fearful self-preservation, but so that another challenge may be faced. He fought with full expectation of being slain, but fought with every atom of his being, for there is no greater joy for the brave than giving everything for what he believes. And if any adversity can conquer the heart and strength of such a powerful force, one who has nothing to lose and everything to gain by exposing his weakness and inviting pain, he will know that he has died gloriously in his love and conviction, and without regret. In truth, he was not conquered at all, for nothing can defeat a fearless heart. When such warriors die, the valkyries then carry them over Bifrost, the rainbow bridge, and to Valhalla. Once in Valhalla they also serve the slain warriors meat and drink. (This should not at all be seen as a servile role, rather just the opposite. Sometimes in Viking society a queen would serve a particularly honoured guest herself, as a sign of great respect, and it is in this sense that the valkyries serve the Einherjar who feast there.)
The descriptions of Odinn's hall describe the Valkyries as foster-daughters, just as the einherjar (the chosen warriors of Odinn) are foster sons Freyja is said to be the first of the Valkyries, called Valfreyja, "Mistress of the Slain," she pours ale at the feasts of the Aesir . The Valkyries also have duties in the great hall. There, having exchanged their armour for pure white robes, they will serve the warriors they have chosen. Another function the valkyries serve in Valhalla is to guide the warriors in their battle-training, and to heal and/or reanimate them after a day of battle-practice. They also give warnings of battle via dreams and visions, and also of impending death.
Sometimes, the Valkyrie guides and protects her chosen human, and may become his lover. She teaches him the ways of Odinn, and brings him wisdom and inspiration from the god, and when the time comes she kills him and brings him home. So that he may celebrate true love in his own skin.
Valhalla, the great hall of slain warriors is located in Asguard, the realm of Odinn. It contains 540 doors each of which leads to a room which can accommodate 800 warriors. The roof is made of warrior's shields. There the warriors spend their days fighting and their nights feasting, until Ragnarok, the day of the final world battle, in which the old gods will perish and a new reign of peace and love will be instituted.
The Valkyries are connected with the legend of the Raven Banner. This banner was woven of the cleanest and whitest silk and no picture of any figure was found upon it except in the case of war, at which time a raven always appeared upon it, as if woven into it. If the Danes were going to win the upcoming battle, the raven appeared with his beak wide open, flapping its wings and restless on its feet. If they were going to be defeated, the raven did not stir at all, and its limbs hung motionless. Sometimes the blood-covered Valkyrie-prophetesses are seen themselves as weavers, to prophesy the outcome of the next day's battle.
The Valkyries are also Odinn's messengers and when they ride forth on their errands, their armour causes the strange flickering light that is called the "Aurora Borealis" (Northern Lights). When the Northern Lights were in the sky, ancestors said that it was caused by the light reflected from the shields the Valkyries were beating their swords against.
Any maiden who becomes a valkyrie will remain immortal and invulnerable as long as they obey the gods and remain virginal. It is often said that if you see a Valkyrie before a battle, you will die in that battlle.