Sweet Devil is a Vocaloid-electropop song by producer Hachiouji-P (八王子P), featuring Hatsune Miku on vocals with lyrics by q*Left. The track first appeared on Hachiouji-P's 2010 album Distorted Princess before being licensed for use in SEGA's rhythm game series. In maimai, it was introduced during the ORANGE PLUS edition (July 2015) as part of a cross-promotional unlock event with CHUNITHM, players who cleared the song in CHUNITHM could play it in maimai, a distinctive early example of inter-game collaboration between the two SEGA arcade rhythm games. Musically, Sweet Devil pairs a driving 132 BPM electro-pop beat with Miku's processed vocals, weaving a narrative about a self-aware "liar girl" who alternates between playful confession and coy denial. The title's juxtaposition of sweetness and devilry is reflected in the lyrics' push-and-pull dynamic. The maimai version is a shortened edit (1:42) that omits the fourth through sixth lyrical sections present in the full-length CHUNITHM version (2:28). The MASTER chart, designed by Techno Kitchen, carries a level 12+ rating with a constant of 12.7, placing it among the more demanding charts of its era in maimai. Its 599 notes include 43 Break notes, and the chart's dense patterning and high scoring ceiling (SSS+ 100.89%) have kept it a recurring challenge for veteran players through multiple version re-levels. The EXPERT chart was designed by mai-Star. In Asian English regional releases of maimai, the artist is credited as 8#Prince instead of 八王子P.