* AnimeFirst: The anime came out in 2004. The first manga adaptation and the light novel were released in 2005.
* ExecutiveMeddling: Oddly, in the favor of the show. The first 11 episodes are generally considered the worst part of the franchise, with none of the characters being particularly interesting or sympathetic. Then the studio replaced the writer at the time with Tow Ubukata, upon which point everything from the characters to dialogue to world-building were massively improved. It was praised enough that Ubukata has been in charge of writing everything (except for the short-lived 2005 manga adaptation) Fafner-related since.
* TheOtherDarrin:
** On the English side of things, Funimation replaced the entire cast (except Creator/StephanieSheh, which surprisingly credited her role under her [[AlanSmithee Jennifer Sekiguchi pesudonym]]) with their regulars. Yes, even ''Creator/JohnnyYongBosch[='=]s'' role as Kazuki (who he normally works with Funimation to either reprise his old roles or get new ones) was replaced by someone else. [[Creator/MicahSolusod Guess who that someone else is.]][[note]]Considering the release dates, the 2nd season of ''Anime/StrikeWitches'' was likely recorded around the same time as the Fafner movie, and Creator/StephanieSheh plays a main character in Strike Witches, so that's probably why they were able to bring Sheh back. Also, Sheh was credited as Jennifer Sekiguchi for that dub, and JYB as "Kevin Hatcher".[[/note]]
** On the Japanese side of things, Hester was voiced in the original series by Creator/ToshikoFujita, but was replaced by Yoshino Ohtori as of ''Exodus''.
* RealLifeRelative: In ''The Beyond'', twin sisters [[Creator/SatsumiMatsuda Satsumi]] and Creator/RisaeMatsuda voice [[spoiler:the twin cores of Tatsumiya, Kaguya and Sakuya Minashiro.]]
* RecastAsARegular: Creator/TsuguoMogami had a minor role as Reo's father, Masakazu Mikado, in ''Exodus'' before being cast as recurring antagonist Legato in ''The Beyond''.
* StudioHop: After Xebec's July 2019 closure, the studio's former parent company Creator/ProductionIG took over production for the remainder of ''The Beyond'' as well as ''Behind the Line''.
* SwanSong: ''Fafner: The Beyond'' was the last-ever project by Creator/{{Xebec}} before its 2019 closure.
----