* CrossDressingVoices: Allen's Japanese voice actor in the first series is Creator/SanaeKobayashi.
* DoingItForTheArt: At this point, after years of hiatuses and with a chapter every 3 months, Hoshino is no longer concerned by cancellation (the Jump SQ Crown mostly publishes one-shots anyway) and can pretty much do whatever she wants with her series. It's very unlikely that the latest volumes would have veered off so much from a traditional shonen formula if the series had stayed weekly.
* HeyItsThatVoice: Allen is voiced by Creator/SanaeKobayashi. In other words, [[Manga/ElfenLied Lucy]]. You may now run away and hide under the bed.
** [[Creator/TakahiroSakurai Kanda]] and [[Creator/KenichiSuzumura Lavi]] were previously friends in [[VideoGame/CrisisCoreFinalFantasyVII Crisis Core]] with their personalities being similar. Kanda and [[Creator/ToshiyukiMorikawa Tyki Mikk]] have clashed before under the names of [[VideoGame/FinalFantasyVII Cloud and Sephiroth]].
** In Funimation's dub, Allen is [[LightNovel/{{Baccano}} Firo]], [[Manga/AxisPowersHetalia Italy]], [[Anime/OnePiece Kohza]], [[Anime/SoulEater Death the Kid]], [[Manga/FullmetalAlchemist Ling]], [[Anime/SgtFrog Keroro]], [[Anime/OuranHighSchoolHostClub Hikaru]], and [[{{xxxHOLiC}} Watanuki]], just to name a few.
** You can clearly hear the [[Manga/{{Naruto}} Tsunade]] in Klaud Nine's voice.
** Winters Socalo is [[Creator/NorioWakamoto Norio motherfucking Wakamoto]]. Although he does make [[{{Hellsing}} Anderson]] act nuts.
* IKnewIt: [[spoiler: The Earl has horns]]. Doubly so for those who read ''Zone'', the oneshot that provided the inspiration for the entire series.
* TheOtherDarrin: In the 2016 series, Allen is now voiced by Creator/AyumuMurase, replacing Creator/SanaeKobayashi.
* TalkingToHimself: Lavi has the same [[Creator/JasonLiebrecht English voice actor]] as the Millennium Earl. According to TheOtherWiki, he was voiced by Creator/ChrisPatton in episodes 27 and 28, and went back to his original actor in episode 40. Some fans wonder what was with all that?
* WhatCouldHaveBeen: Creator/ToddHaberkorn, also the director, knew about the Black Order members being British, and contemplated putting those accents on them. He decided against it because the test recordings made Allen sound harsher and less appealing, and their natural accents would be easier on the actors (this was when they had planned to dub the show to the end, like a long-runner).
** Lavi was originally intended to be main character for the series called "BOOK-MAN", a project which never reached beyond the planning stages. Still, the author wanted to use him and Bookman so they made it into ''D.Gray-man'' as side characters instead.
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