火炎地獄 (Kaen Jigoku, "Flame Hell") is an instrumental track composed by Michiru Yamane and arranged by Keitarou Hanada, added to maimai during the GreeN PLUS era on May 15, 2014. Yamane, best known in the broader game-music world for her work on the Castlevania series (Symphony of the Night, among others), brought a progressive-rock sensibility to maimai's original song roster. Hanada, whose credits include the Yakuza (Ryū ga Gotoku) series, handled the arrangement, replacing Yamane's programmed guitar parts with live演奏 that, by her own account, exceeded her original vision in raw intensity. The track is a hard-and-heavy electric guitar showcase built on gothic classical phrasing and shifting time signatures, clocking in at a relentless 216 BPM. Despite its rhythmic complexity, the composition flows smoothly enough that the odd meters feel natural, a hallmark of Yamane's game-music craft. The title, decided after the final arrangement was complete, evokes the image of blazing hellfire, and the in-game jacket reinforces that with a monster engulfed in flames. At launch, 火炎地獄 was locked behind a steep 100,000 maimile gate (later reduced to 100 music tickets before becoming free in ORANGE PLUS). Its Standard MASTER chart, designed by mai-Star, was one of the first Lv.12 MASTER charts in the game and held a reputation as a demanding stamina check. In 2022, DX charts arrived via maimai でらっくす FESTiVAL, adding a new MASTER chart by はっぴー that incorporates heavy Touch-note usage, 309 Touch notes out of 824 total, making it an unusually tactile experience for a song of this era.