"Estahv" (エスターヴ) is a high-energy original track by Japanese composer and vocalist Feryquitous, appearing in maimai DX UNiVERSE PLUS as part of the Diverse System collaboration area. Clocking in at 191 BPM, the song belongs to Feryquitous's self-described "v" series, a set of compositions unified by a shared creative framework: a targeted velocity, a curated palette of instruments, lyrics in a fictional language built from recurring root words, and sung vocal delivery at the core of every arrangement. Each entry in the series takes its title from a concept that represents a single-direction vector of emotion or action, though the composer leaves the precise interpretation to the listener. Originally released on Feryquitous's fourth solo album 白戒 (2019), the version used in maimai is a gamesize edit lasting roughly two minutes. The lyrics, presented in a constructed language with no direct Japanese or English counterpart, contribute to the track's otherworldly atmosphere, a hallmark of Feryquitous's style that blends symphonic elements, hard-hitting synth leads, and ethereal vocal layering. In maimai, the song received DX charts across all four standard difficulties, with the Expert chart designed by はっぴー and the Master chart by 翠楼屋, the latter rated 13+ (constant 13.8). Initially locked behind a 100-kilometer distance milestone in the Diverse System area during UNiVERSE PLUS, Estahv became available by default starting with maimai DX FESTiVAL.