Dr. Matsumoto's personality emerged through narrative developments. He confined Vivy to a museum after she lost her singing ability. Subsequently, Dr. Matsumoto collaborated with Vivy on a years-long mission. This collaboration involved assistance from a young boy who grew from childhood to adulthood during the project; later, that boy's own child also joined their efforts. Dr. Matsumoto's actions ultimately contributed to a situation where artificial intelligences employed humans, utilizing a distorted rendition of Vivy's song to sustain their operations.