* TheDanza: Yoko Maki as Yoko.
* ExecutiveMeddling: Kayako did not have much of a backstory in the original film series, and Takashi Shimizu wanted to keep it that way. However, he was told to give her a backstory for ''The Grudge 2'', which he reluctantly went ahead with . In an interview, Shimizu also stated that executives kept insisting that Kayako should have "a twin", which baffled him. In ''The Grudge 3'', Kayako is revealed to have a sister (though not a twin sister), which has to make one wonder if that was a case of executive meddling, too.
* HeyItsThatGuy:
** Creator/SarahMichelleGellar as Karen is the most obvious example.
** Aubrey is played by [[Series/JoanOfArcadia Amber Tamblyn]].
** Ryo Ishibashi, who plays Detective Nakagawa, is well-known for his roles in ''Film/{{Audition}}'' and ''Film/SuicideClub''.
** Alex is played by Ted "[[Series/XenaWarriorPrincess Joxer the Mighty]]" Raimi, Sam Raimi's brother.
** Isao Yatsu, who plays [[{{Expy}} the senile old man on the bus]], also appeared in the third ''Ju-on'' movie playing a similar role, and previously appeared as the apartment manager Kamiya in ''Film/DarkWater''. He also had a part in ''Film/{{Infection}}''.
** Yoko Maki, [[TheDanza who plays Yoko]], has appeared in ''LightNovel/KamikazeGirls'', ''Film/{{Infection}}'' and ''Literature/BattleRoyale II: Requiem''.
** This also isn't the first time that Creator/SarahMichelleGellar and Jason Behr (Doug) have appeared on-screen together - Behr played Billy Fordham in the ''Series/BuffyTheVampireSlayer'' Season 2 episode "Lie To Me". Additionally, Clea [=DuVall=] (Jennifer) appeared in a Season 1 episode, "Out of Mind, Out of Sight".
** Additionally, Clea [=DuVall=] and [=KaDee=] Strickland (Susan) have previously appeared in another movie together, ''GirlInterrupted''.
* TheOtherDarrin:
** As with the original ''Ju-on'' series, Toshio has been portrayed by three different actors. In the first film and in flashbacks/photographs for the second and third films, he was portrayed by Yuya Ozeki (who also portrayed the version of the character in the two theatrical ''Ju-on'' films). In the second film, he was portrayed by Ohga Tanaka. In the third film, he is portrayed by Shimba Tsuchiya. (Unfortunately, the difference is rather jarring in the third movie, as Toshio looks a lot older than in the previous films.)
** Not only that, but Creator/TakakoFuji, who has played Kayako from the very beginning of the ''Ju-on'' saga up until ''The Grudge 2'', has been replaced in ''The Grudge 3'' by Aiko Horichi (although Fuji does appear as Kayako in the third movie's flashbacks and photographs). According to [[WordOfGod Takako Fuji herself]], she was getting tired of playing the same role over and over again. Also, in the ''Tales of the Grudge'' shorts, Kayako is portrayed by Anna Moon.
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