Masamune Usami is a supporting character in the anime series Mayo Chiki!. She is a member of the S4, a group of popular girls at the school, and is known for her cheerful and friendly personality. Masamune has a crush on the main character, Kinjirou Sakamachi, and often finds herself entangled in the comedic and romantic situations that arise throughout the series. Despite her seemingly carefree demeanor, she is also shown to be caring and considerate, particularly towards her friends and those she holds dear.