躯樹の墓守 (Mukuroju no Hakamori) is an original maimai composition created for the 7sRef area's Perfect Challenge in maimai でらっくす UNiVERSE. The track was produced by the composer unit 隣の庭は青い (Tonari no Niwa wa Aoi), a collaboration between NIWASHI (庭師) and Aoi, two artists whose individual styles converge into a driving, high-energy soundscape befitting the song's 211 BPM tempo. The title, confirmed by NIWASHI to read むくろじゅのはかもり, evokes imagery of a guardian standing watch over a corpse tree, and the song's atmosphere matches that ominous gravitas with relentless percussion, rapid-fire synth lines, and a mounting intensity that never lets up. Within maimai, the track is best known for its MASTER chart (level 14+, designed by 超七味星人), which pushes players with dense patterning, high note density (1,038 total notes), and a notorious final section featuring rapid spinning motions, patterns that the community has noted may have inspired or anticipated similar rotational sections in the later maimai song 系ぎて. The EXPERT chart (designed by はっぴー) was originally released at level 12+ and later re-rated to 13 starting from the FESTiVAL version, reflecting the chart's genuine technical demand. The song's accompanying video was produced by 鑓田 (alpha complex), whose visual direction complements the track's dark, futuristic worldbuilding.