Sumika Aoyama is a central character in the anime series 'Koisuru Kanojo no Bukiyou na Butai.' She is portrayed as a shy and introverted high school student who struggles with expressing her feelings. Despite her reserved nature, Sumika has a deep passion for theater and dreams of becoming a playwright. Her journey throughout the series involves overcoming her fears and insecurities, as she learns to open up to others and embraces her talents. Sumika's character plays a crucial role in the series, as her development and relationships drive the narrative forward.