Eisen Flügel[a] (アイゼンフリューゲル, Aizenfuryūgeru) is a Japanese light novel series written by Gen Urobuchi and illustrated by Higashiguchi Chūō.

The series was published in two volumes under Shogakukan's Gagaga Bunko light novel imprint from July to December 2009.

[4] The series later moved to Shogakukan's MangaONE app, where it ran from December 17, 2017,[5] to September 16, 2018.

On September 24, 2022, during the Aniplex Online Fest 2022 event, an anime film adaptation produced by A-1 Pictures was announced.

The film is directed by Daizen Komatsuda, with Seiji Mizushima serving as chief director, Yukie Sugawara writing the screenplay along with Mizushima, Keigo Sasaki adapting Takashi Takeuchi's original character designs for animation, Kanetaki Ebikawa, Takayuki Yanase, and Fumihiro Katagai serving as mechanical designers, Tatsuya Yoshikawa serving as dragon designer, and Yuki Kajiura composing the music.