Masako Natsume is a supporting character in Mawaru Penguindrum and one of the younger Natsume siblings. She is a cool, sharp-tongued, and highly capable girl who often acts as an enforcer within her family’s schemes. Masako plays an important role in the story by helping drive the Natsume family’s secretive and manipulative actions, while also revealing the tensions and dysfunction beneath their polished image. Her presence adds both menace and complexity to the series.