Ne! Ko! (ネ！コ！) opens the TV anime adaptation of NORA, Princess, and Stray Cat (ノラと皇女と野良猫ハート), a visual novel by HARUKAZE that blends supernatural comedy with a cast of colorful characters. The title itself is a playful, punctuated spin on "neko" (猫, cat), splitting the word with exclamation marks to mirror the series' feline motif. Composed and arranged by Shintarou Mori with lyrics by Hato, the track features all four leading voice actresses from the anime performing in character, Natsumi Takamori as Patricia of End, Eri Sendai as Michi Kuroki, Yuu Asakawa as Shachi Yuuri, and Atsumi Tanezaki as Yuuki Asuhara, with vocal direction and chorus by Yura Hatsuki. The song joined maimai FiNALE as part of its December 13, 2018 launch lineup under the POPS & ANIME category. Before arriving in maimai, it had already debuted in CHUNITHM STAR PLUS earlier that year, and it would later cross over into ONGEKI as well, making Ne! Ko! one of the shared tracks bridging SEGA's three major arcade rhythm game platforms. In maimai, both the EXPERT and MASTER charts were designed by 玉子豆腐 (Tamagodoufu), and the MASTER chart has undergone several level revisions across the DX era, reaching as high as 13 before settling at its current 12+.