Perhaps the most powerful of the Old Ones. Though physically as frail as a bird, she is a very powerful figure in the books, especially in the The Dark is Rising and Silver on the Tree.
Though she makes infrequent appearances throughout the series, they are usually at important moments which will turn the tide in the Light's favor. She is, however, as a figure of the High Magic (above Light and Dark) able to be an impartial judge, such as when The Rider for the Dark challenges Bran Davies' right to be part of the final battle in Silver on the Tree. She always wears a rose-colored ring. She names herself as "Juno" (Queen of the Gods) to Jane Drew, but is more likely Robert Graves' Dana/Don - the White Goddess. She is all that is good and powerful, from a Marian figure to Britannia, the female image of Britain itself. She could be the Lady of the Lake, or the Lady of Avalon. She also acts like the embodiment of Justice at the end of Silver on the Tree.