Tsumugi Kotobuki, often referred to as 'Mugi,' is a main character in the anime series K-On!. She is the keyboardist of the band Ho-kago Tea Time. Known for her gentle demeanor and affluence, Mugi comes from a wealthy family and often provides the band with resources such as instruments and practice space. Her kind-hearted nature and curiosity about everyday life make her a beloved character. Mugi's passion for music and friendship deeply influences the dynamics of the group, adding warmth and support to their high school adventures.