Paradisus-Paradoxum is a high-energy J-rock track by the Japanese multimedia project MYTH & ROID, serving as the second opening theme for the first season of the anime Re:Zero -Starting Life in Another World- (Re:ゼロから始める異世界生活). Composed, arranged, and written by Tomohiro Oshima and sung by Mayu, the song was released as a single in 2016. Its driving beat, rapid-fire guitar riffs, and frantic vocal delivery match the show's intense narrative, and the BPM of 201 makes it one of the faster songs in the maimai rhythm game series. The song was added to maimai MURASAKi PLUS at launch on June 22, 2017, with Standard-difficulty charts. Several years later, on July 31, 2020, it received new DX-format charts in maimai でらっくす PLUS, bringing the total to four DX difficulties. The Standard Master chart (level 13) was designed by はっぴー, while the DX Master chart (level 12+) was designed by シチミヘルツ. Both are known for dense note patterns that test players' endurance at high speed. Due to licensing restrictions, Paradisus-Paradoxum was never made available outside Japanese arcade cabinets and was ultimately removed from all maimai machines on March 23, 2023. It remains playable in other Sega rhythm games such as CHUNITHM and ONGEKI, where longer cuts of the song appear.