Valkyrie in Norse mythology, any of a group of maidens who served the god Odin and were sent by him to the battlefields to choose the slain who were worthy of a place in Valhalla. These foreboders of war rode to the battlefield on horses, wearing helmets and shields; in some accounts, they flew through the air and sea. Some Valkyries had the power to cause the death of the warriors they did not favour; others, especially heroine Valkyries, guarded the lives and ships of those dear to them.