Tsumugi Kotobuki is a fictional character from K-On! She is otherwise known as Mugi. She is a wealthy cheery cute girl with a gentle personality who plays the keyboard in the light music club. She was originally going to join the choir club, but after Ritsu Tainaka's false flashback she thought it would be fun to join the club. This character is popular among cosplayers. It can be portrayed by wearing cosplay Tsumugi Kotobuki costume and cosplay Tsumugi Kotobuki wig. This character is always present in a K-On! cosplay.