Matsumushi is a very young little girl that seems to have exceedingly good eyesight.She is meant to be "the eyes of Seimei, while Seimei is meant to be "her ears". Matsumushi seems hold a large amount of various medicine with her, such as in the case when she handed medicine to Seimei when they were in quick need of healing the Capital's emperor. Because Matsumushi can not say a single word, it is not known if she follows Seimei through affection, or through configured loyalty set by Seimei. Either way, Matsumushi seems to follow Seimei to any area and is occasionally seen as Seimei's second half.