Saikōsoku Fall in Love

"Saikōsoku Fall in Love" (最高速 Fall in Love, lit. "Highest Speed Fall in Love") is the first opening in the series sung by the voice actresses for Miia, Papi, Centorea, Suu, Mero, and Rachnera.

Renditions of the song also appear in each of the Character Album soundtracks, with the album's featured character singing the entirety of Saikōsoku Fall in Love solo.

Trivia

 * The final scene in the opening song video is a reference to Son Goku's Spirit Bomb technique from the Dragon Ball franchise.
 * In each of their solo renditions of the song, Miia, Papi, Centorea, Suu, Meroune and Rachnera refer to "Darling" with the nickname they use to refer to Kimihito in the manga/anime. As such, Miia says "Darling", Papi says "Goshujin", Centorea says "Aruji-dono", Suu says "Master", Meroune says "Danna-sama" and Rachnera says "Honey".
 * The first few seconds of the opening have the same melody as the Spanish National Anthem.