Gensou Airly is a group featuring the Vocaloids Kagamine Len, KAITO, Camui Gackpo, and Hiyama Kiyoteru. The group was created by Pantan-C, Pantan-D, and Ayaka (also called the Pantans). Most of the songs from this group feature Len, KAITO, Gackpo, and Kiyoteru. However, one song, "Battle Royal Valentine", features MEIKO, Hatsune Miku, Kagamine Rin, Megurine Luka, GUMI, and SF-A2 miki. This song is a prequel to the song "Your Highness☆My Princess". "Battle Royal Valentine" is about the girls preparing to "battle" against time and other girls to give chocolates to the boys on Valentine's Day, while "Your Highness☆My Princess" is a reply to this song.