Masashi, known as Ma-kun, is the younger brother of Saki, a third-year transfer student. He and Saki initially planned to take over the Magic Club and convert it into a Street Performance Club, but they ultimately joined the existing Magic Club alongside Sempai and Assistant. Masashi possesses a level-headed and reasonable personality, forming a distinct contrast to his sister's eccentric and obsessive nature. His temperament shares similarities with Assistant's, making him one of the more grounded members within the often-unpredictable club dynamic. Masashi maintains an interest in psychology and behavior analysis. His relationship with Saki is complicated by her excessive affection and possessiveness toward him, which causes him discomfort and prompts attempts to create distance; however, he still cares deeply about her well-being and worries she might cause public embarrassment during their performances. Physically, Masashi is depicted as obese. Within the Magic Club, he performs balloon tricks alongside his sister, contributing to club activities despite his initial lack of connection to magic. He consistently maintains a calm demeanor even amid the club's frequent chaotic situations.