おねがいダーリン (localized as ONEgai Darling in Asian English regions) is a vocaloid pop-rock song performed by ONE, the voicebank developed by 1st PLACE as a successor to the well-known IA. The track was composed, arranged, and written by Takashi Iwami under the circle name Nanahoshi Kangengakudan (ナナホシ管弦楽団), and originally appeared on the 2015 album ONE/00. The title carries layered wordplay: "おねがいダーリン" combines the Japanese entreaty "onegai" (please / wish) with the English loanword "darling," while the localized "ONEgai Darling" folds in the vocalist's name. Lyrically, the song captures a one-sided conversation in which the narrator, alternating between exasperation and teasing affection, pleads with an uncommunicative partner to open up. Lines such as "Your heart is pitch black" and the repeated refrain "おねがいダーリン" paint a portrait of a relationship strained by silence. The 180 BPM arrangement drives forward with energetic guitar riffs and punchy synth accents that mirror the narrator's restless frustration. Added to maimai MiLK PLUS on August 7, 2018, おねがいダーリン has remained a fixture of the game's niconico & VOCALOID category ever since. It also crossed over into CHUNITHM and received a separate human-voiced cover by Matsushita for オンゲキ, making it one of the few vocaloid tracks to appear across all three of SEGA's rhythm game series.