STARTLINER is the main theme of SEGA's arcade rhythm game Ongeki (音撃), composed by the prolific electronic producer kz(livetune), widely recognized for pioneering Vocaloid tracks such as "Tell Your World" and "Packaged," as well as producing for Hatsune Miku and a wide range of anime artists. The song is credited to the Ongeki Shooters (オンゲキシューターズ), a collective name for Ongeki's vocal cast that shifts per track; for STARTLINER, the performers are the three voice actresses of ASTERISM, Ongeki's central protagonist unit: Hikaru Akao as Akari Hoshizaki, Risa Kubota as Yuzu Fujisawa, and Anzu Haruno as Aoi Misumi. The jacket art depicts the three characters in their signature poses against a starry, cosmic backdrop. Released in Ongeki in 2018 as the game's flagship opening track, STARTLINER crossed over to maimai on July 26, 2019, as part of the first maimai DX (でらっくす) version. It was one of the very first two songs, alongside "Jump!! Jump!! Jump!!", to be ported from Ongeki to maimai, marking the beginning of ongoing cross-franchise collaboration between the two SEGA rhythm-game families. Initially slotted under the Original genre, STARTLINER was moved to the Ongeki & CHUNITHM category in the maimai DX PLUS update. The maimai chart suite covers all five DX-standard difficulty tiers. The Master chart (level 11+, constant 11.6) was designed by ロシェ@ペンギン, known for intricate Slide and Touch-note choreography, and the Expert chart (level 9) by 華火職人. A Re:Master chart (level 12, constant 12.3) designed by はっぴー was added later on November 24, 2023, several years after the initial release; it packs 567 notes with a notably dense 131 Touch notes, demanding precise multi-finger coordination.