* ActorAllusion:
** Kurosawa apparently has a troubled past with a love letter that Yukari threatens to blackmail her with if she reveals any of Yukari's schooltime shenanigans. Kurosawa's voice actress, Aya Hisakawa, also played [[Anime/SailorMoon Sailor Mercury/Ami Mizuno]], who gets a special in the anime and manga dedicated to a romantic notion of hers. In it, she's shown to have a strong aversion to love letters, culminating in an allergic reaction to some that are used to attack her in the climax.
** Kaorin's German voice actress, Kathrin Neusser, played Mayu from ''Manga/ElfenLied'', a character who looks ''very'' similar to Kaorin.
* HeyItsThatVoice:
** [[Creator/NorioWakamoto Chiyo's "dad"]] is [[Anime/DragonBallZ Cell]], [[Anime/CowboyBebop Vicious]], and [[Anime/CodeGeass Emperor Charles zi Britannia]].
*** Funny enough, in English he's also [[Anime/DragonBallKai Frieza's dad a.k.a King Cold]] and [[Franchise/OnePiece Aokiji/Kuzan]].
*** And he gets his wish to become a bird in the VisualNovel/HatofulBoyfriend drama [=CDs=].
** In Japanese, Osaka has the same voice actor as [[Manga/{{Bleach}} Orihime Inoue]] and [[MahouSenseiNegima Evangeline A.K. McDowell]], Yuki Matsuoka.
*** Yuki Matusoka also voiced another Osakan: Aiko Senoo from ''Anime/OjamajoDoremi''
** In English, [[Creator/LuciChristian Yukari]] is one of [[LightNovel/FullMetalPanic The Whispered]]. She's also [[OuranHighSchoolHostClub Hunny-senpai]] while Nyamo is Renge.
** Yukari [[AkikoHiramatsu is]] [[SaberMarionetteJ Bloodberry]], [[YoureUnderArrest Miyuki Kobayakawa]] and [[FlameOfRecca Fuko Kirisawa]] in the Japanese version
** Another English one, Chiyo's dad (Jason Douglas) is [[Anime/ExcelSaga Il Palazzo.]]
** Joining her Anime/ExcelSaga co-star is TiffanyGrant playing Kaorin.
** [[TiffanyGrant Kaorin]] is also [[Anime/NeonGenesisEvangelion Asuka Langley-Soryu.]]
** Sakaki is [[Manga/FullMetalAlchemist Izumi Curtis]] in English.
** [[Creator/AyaHisakawa Nyamo]] is [[Anime/SailorMoon Sailor Mercury]] and [[Anime/{{Bleach}} Captain Retsu Unohana]].
** [[Creator/YukiMatsuoka Osaka]] is [[Manga/{{Bleach}} Orihime Inue, Young Ichigo Kurosaki]] and [[Manga/MagicalShoppingArcadeAbenobashi Arumi Asahina.]]
*** in English she's [[Anime/PuniPuniPoemi Hitomi Aasu,]] [[Anime/PaniPoniDash Ichijou's Little Sister, Suzune Shiratore]] and [[Anime/NerimaDaikonBrothers Pandaikon.]]
** English again, Mr. Kimura is also [[AngelicLayer Ichiro 'Icchan' Mihara]], in both voice and, vaguely, appearance.
* RelationshipVoiceActor: The German cast of ''Manga/AzumangaDaioh'' has voice actors that played characters from ''Manga/ElfenLied'' and ''Anime/NeonGenesisEvangelion''.
** Rubina Kuraoka played Chiyo-chan and Nana.
** Samia Little Elk played Sakaki and Lucy/Nyu and she plays Rei in ''[[Anime/RebuildOfEvangelion Rebuild]]''.
** Jennifer Weiß played Osaka and Mariko and she plays Mari.
** Julia Kaufmann played Yukari-sensei, Yuka and Misato prior the ''Rebuild''-era.
** Kathrin Neusser played Kaorin and Mayu. The fact that both characters look very similar is also an ActorAllusion.
** Julia Ziffer played Tomo and still plays Asuka.
** Jesco Wirthgen played Male Student #1 and Kohta.