Yoko Littner (played by pyrololita) is an angel and current student of Spirit High.
Yoko was a guardian angel serving in Heaven for quite some time who had begun to grow bored with the whole deal of it, much like Roxanne, who ended up breaking the rules of no violence by injuring a group of demons and was subsequently banished from Heaven, becoming a fallen angel.
Roxanne was sent to Spirit High to learn how to become a better, more peaceful angel, and Yoko, seeing this as a chance to live out being a teenager like she had never experienced in life, followed her without care and soon ended up as a fellow student at the school.
Yoko is generally kind and cheerful, happy to help as an angel should be. She is still a guardian angel, and so maintains many of her angelic qualities such as a fierce protection over the weak and the friends she has made at Spirit High. She is slightly naive, however, and not used to Earth, so she is still new to everything.