The daughter of the president of Daidouji Toy Company, Sonomi Daidouji, Tomoyo lives a life of wealth and is watched over by a team of female bodyguards. She has access to a variety of prototype technological gadgets from her mother's company, and supplies Sakura and Cerberus with different communication devices throughout the series. She is depicted as being mature, kindhearted, intelligent, and regularly speaking using more formal verb conjugations and expressions than normally seen in elementary students. She is a talented singer, and is shown performing in various school events. In the anime, her musical ability causes her to be targeted by both the Voice and Song cards.