Matsuri Dei (出で井い 祭まつ李り, Dei Matsuri?), is a character in The 100 Girlfriends Who Really, Really, Really, Really, Really Love You. She is Rentarou's 27th girlfriend, a third-year student at Ohananomitsu High School, in class 1-2, and a yakisoba seller. Matsuri is half-British, and her mother comes from England while her father from Japan. Both of her parents are fashion designers, specializing in the Gothic Lolita style, and she wears their designs as her everyday clothing. Matsuri lives with her grandparents due to her parents being overseas for work. Her grandparents run a yakisoba stand at festivals, and she regularly helps them out at their stand. Despite her prim and proper appearance, Matsuri speaks in the rough Shitamachi dialect associated with the working-class of Tokyo, and has a habit of rolling her sleeves up to her shoulders. Matsuri loves festivals, and is initially upset after believing that Rentarou only attended festivals as a way to score girls. However, she falls in love with Rentarou when he proves that he genuinely appreciates festivals for the experiences they provide.