The Crow familiar. Her knight partner is Shinonome Mikazuki.
An enigmatic pitch-black crow. Her features are rarely detailed.
Interestingly, Muu never speaks at all. She remains in the shadows as if she was not really there at all. She has only been noted to have spoken twice, once when Shinonome Mikazuki made his contractual wish and again right before she disappears with the other animals. It was revealed that Muu is a female at the very end of Yuuhi and Mikazuki's final battle. Much to the suprise of the other knights and even the other animals. Muu is apparently the only female animal familiar.