Kanna Udou is a key character in the anime series 'Air.' She is a winged being, or 'Tori no Hito,' from the Heian period and is central to the story's tragic past. Kanna is depicted as a spirited yet lonely princess who longs for freedom and connection, especially with her guardians, Ryuuya and Uraha. Her fateful journey and forbidden love set the foundation for the series' emotional themes of memory, reincarnation, and the search for happiness across time.