Masaki Akemiya is a high school student and a classmate of Sumika Murasame, Ushio Kazama, and Kiyori Torioi in the series Sasameki Koto. He is the older brother of Manaka Akemiya. At first, Sumika does not pay much attention to him until he tells her that he thinks she is cute, which catches her attention because she longs to appear cute for Ushio. Masaki is a shy and introverted boy, but he is also sociable, empathetic, and emotionally perceptive. He develops romantic feelings for Sumika and, after realizing that she is in love with Ushio, he is persuaded by his younger sister Manaka to cross-dress in order to attract Sumika's attention. Manaka secretly sends a photograph of him in a feminine outfit to a magazine, which leads to him being hired as a fashion model under the female persona Akemi Yamasaki. Masaki finds the situation embarrassing but goes along with it, even appearing in public dressed as the model to confiscate copies of the magazine. He eventually confesses his feelings to Sumika, who gently rejects him, explaining that her heart belongs to Ushio. Despite this, Masaki remains a supportive friend. He later cross-dresses again at Sumika's request to help gather information for the Girls Club. When Ushio meets him in his female persona, she finds him very cute, which causes Sumika additional distress. After being publicly exposed as a cross-dresser, Masaki stops modeling. Throughout the story, he serves as a confidant and an unexpected source of insight into the characters' emotional struggles. His easygoing and accommodating nature makes him a well-liked presence in the group, and his experiences highlight themes of self-acceptance and unrequited love.