Valkyries are the physical forms of very rare souls (called modir by the Gods) that only take the form of woman. Valkyries possess the unique ability to gaze upon the spirits of humans (firar) and foresee their past and future. They may also project thoughts directly into their minds. They may also guide these spirits out of their human vessels and into the afterlife.
Because of this very ability, modir are sought after by the Gods of Asgard. They make for the perfect caretakers, recruiters of human souls. However, unlike the normal human spirit, modir are not easily controlled. They cannot be guided, and unlike firar, are immune to the magical field that protects the gateway realm of Yggdrasil. In essence, once free of their human vessel, modir’s are impossible to capture. Gods must lure, trick, or convince them to join their cause. Once transferred into a new physical vessel, they become Valkyries. If successful in recruiting a valkyrie, the God will bestow his mark as a tattoo upon her face, a trophy claiming rights.
Valkyries spend most of their time roaming Midgard and Yggdrasil, seeking the spirits of skilled warriors that will soon befall death. It is a common misconception among Einherjar (Warriors of the Gods, Physical vessels containing the firar they recruit) that the valkyries serve them mead and beverages every night, during a celebratory feast in the great halls of Valhalla. However these are fakes created by the Gods. There purpose is to keep the men at bay and give them purpose for their daily conflicts.
Valkyries are prized by Gods and Men alike. There concern for the human spirit is almost motherly. They see the human soul in a different light, not as a tool to be used by the gods, but as a beautiful essence of a once greater life form.