* CastingGag: Koyasu who voices Dio Brando in the ''Manga/JoJosBizarreAdventure'' TV anime previously voiced Takuma Saioh from ''Anime/YuGiOhGX'', who used an Arcana Force deck, cards of which are based off the Major Arcana, and whose signature monster is: "Arcana Force XXI - ''The World''"
* FanNickname: "Koyappi", at times.
* PlayingAgainstType: Most notably... '''[[VideoGame/TheKingOfFighters Shingo Yabuki]]'''. For this once, Koyasu is a bumbling (but still HotBlooded) AscendedFanboy who idolizes TheHero (in this case Kyo).
** Many argue that his role as Bobobo is also this trope for him. He's an extremely crazy variant of TheHero that wields a power that counts as a GRatedDrug.
** There's also his turn in ''Manga/{{Pretear}}'' playing Tanaka, the squeaky-voiced, comical ButtMonkey butler.
* PromotedFanboy: Of ''Franchise/{{Gundam}}''
* RelationshipVoiceActor: As above, with Creator/HikaruMidorikawa.