Maria Nagai, previously known as Kashiwagi Kurumi, is an AV actress from Japan. She is a support member of Black Diamond, J-Pop Group consisting of three other famous Idols (Anri Okita, Ai Sayama and Mary Tachibana). Her sister is Reiran Akame. As of November 2025, Maria has amassed 763,000 followers on Instagram, 846,000 followers on TikTok and 28,300 subscribers on her YouTube platform.