It was released by Mastersix Foundation on July 4, 2024, as the opening theme for the second season of Japanese anime series Oshi no Ko.

On the same day, the artist's website was launched to countdown for more details,[1] including letters from members,[2][3] some lyrics,[4] and liner notes.

[5] The identity of the artist was unveiled on June 30, to be Kento Nakajima and Tatsuya Kitani, as well as the song's release date, July 4, 2024.

[6] The CD single format—"Gemn", "Anime", and standard—was released in Japan on September 4,[7] and internationally by Black Screen Records in October 2024.

[8] An accompanying music video for "Fatal" premiered via Kitani's YouTube channel on July 5, 2024.