Morrigan also known as Morrigu (the Great Queen or Phantom Queen), was a triplicity of Valkyries--Badb (Crow), Macha (Also Crow), and Nemain (Frenzy). Here again, as in Norse mythology, she [they] would have the right to choose of the slain warriors who would be escorted to the afterworld or otherworld. Those that were "unworthy" so to speak would become part of what is known as "Morrigans acorn crop" - which is the nice way of putting the Valkyries claiming their heads as trophies, or at least that is how the legend goes. She [they] are very diverse in all aspects, and have been closely associated with water, rivers in particular.

Morgan Le Fey has a key role in the Arthurian cycle. Described as a female human, who is educated in magick, she is always at odds with Arthur [she is his maternal-half-sister]. Though there is much debate on whether or not the two are both in the same. The reason why these two names (Morrigan and Morgan) may be linked together is that Morgan was written into the Arthurian stories as the plotter of his death and is associated as the "Goddess of Death." Though I cannot find any research actually basing Morgan Le Fey as a Valkyrie.

"The costume of the ancient Irish bard consisted largely: of feathers the poet as bird/man, the poet as Angel, or direct disciple of the Angel, Muse, White Goddess." Could this be related to an angel encounter?

"Irish Mythology – Nature Spirits

In Irish Mythology, the fairies are the Tuatha de Danaan, the divine race who are children of the goddess Danu. The Tuatha De, or "people of the goddess," as they are called, came over the sea from the east in clouds and mist in the 15th century B.C.E. They were strong and beautiful people, skilled in the magical arts. After taking control of Ireland, they retired into the hills and mounds (side or sidhe) and became underground dwellers who evolved into fairies. In some myths, Tuatha De also remained above ground, where they were renowned for their warrior skills, beauty, wizardry and magic. They were part mortal, part spirit and part god, and they intermarried with humans.

Medieval romances portrayed human characters as fairies; up to the 13th century, having fairy blood was considered desirable. It is possible that these medieval fairies were descendants of small races, such as the Lapps, Picts and Ramano-British-Iberian peoples, who populated Britain, Europe and Scandinavia in the Neolithic and Bronze Ages and were pushed out by larger races such as the Celts. As they retreated more and more into the woodlands, successor races increasingly associated them with superstition." (Encyclopedia of Ghosts and Spirits, Guiley)

The Valkyries are beautiful young women, mounted upon winged horses and armed with helmets and spears. They ride the winds to battle fields in groups of seven. nine, or twelve. Once there they are to choose the bravest and most courageous men from among the slain and return them to Valhalla [Valhalla is the banquet hall (in Norse Mythology) where the principal god, Odin, played host to the Einherjar, the souls of warriors who had died a courageous death in battle] there the men would drink both mead and ale from the skulls of those they had defeated.

During their movement from this world to the next, the Valkyries crossed over a rainbow bridge connecting heaven and earth. It is said that when they rode upon the winds their armor would create strange flickering lights in the northern sky (Aurora Borealis). Before their role as carriers of the souls, the Valkyries of older Norse Mythology originally may have been Priestesses of Freyja, Queen of Heaven. "The Germanic Shield-Maiden Brynhilde is also said to be a Valkyrie; and the three maidens who loved Volund and his two brothers, Hladgud Svan-Hvit, Hervor the Wise, and Olrun were also Valkyries. Note a close parallel here with the Celtic Morrigan." Note: Brynhilde is also spelled Brunhilde.