In Norse mythology, a valkyrie is one of a host of female figures who choose those who may die in battle and those who may live. Selecting half of those who die in battle, the valkyries bring their chosen to the afterlife hall of the slain, Valhalla, ruled over by the god Odin. There, the deceased warriors become einherjar. When the einherjar are not preparing for the events of Ragnarök, the valkyries bear them mead.
Valkyries are described as beautiful women wearing armor and boasting white wings. They also appear as lovers of heroes and other mortals, where they are sometimes described as the daughters of royalty, sometimes accompanied by ravens and sometimes connected to swans or horses.
Valkyries are seen throughout Castlevania, although they mostly populate the Inner Quarters along with Persephones. They wear Norse helmet, armor and boots, with a long loincloth covering their lower body. They attack by first flying near Soma and then lunging with their lance at him.
Obtaining a Valkyrie's soul enables Soma to summon her as a bullet soul. When summoned, a Valkyrie covered in a blue aura will attack by swinging her sword upward. She is among the few souls that deal Holy damage to enemies, though she is among the highest class of damage-dealers in the Bullet Soul class.
The Valkyrie returns to Celia's castle to face Soma. She is depicted as a warrior with a pretty face but with a wicked heart. She is still decked out in a set of Norse armor with a white pair of angelic wings, and attacks horizontally with a lunge of her lance. Her shield now has a symbol of a dragon on it.
Valkyries can be found within the Guest House, although in Celia's castle they attack alongside Liliths. They are also situated in the Dark Chapel. A defeated Valkyrie occasionally drops a Breastplate and, strangely, also drops Pancakes.
Valkyrie's soul is activated as a Guardian Soul and allows Soma to transform him into one of them, as long as it's activated. When transformed, it costs 30 MP per second to maintain the state. While in this state, the Valkyrie attacks by charging in a straight line, uncontrollably hitting all within range with Holy-type damage. The transformed valkyrie abandons her helmet and allows her blue hair to flow while she charges at an enemy.
Soma can also allow Yoko to pry a Valkyrie out and fuse her with either of two weapons, the Great Sword or the Halberd. Upgrading the Great Sword allows Yoko to create the Durandal, a giant sword tempered by fairies (Great Sword class), while upgrading the Halberd will create the Lance, a spear used by knights (Spear class).