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Rikka got the idea for her chuuni persona from Yuuta.There's a momentary flashback in episode 8 where a younger Rikka is looking up at a balcony where a younger Yuuta is being hammy as his Dark Flame Master persona. What are the two most prominent things about Yuuta's DFM persona, even in regular school clothes? That he has his right eye covered and one of his arms bandaged. What about Rikka? That's right, her right eye is covered and one of her arms is bandaged up. As a follow-up to this idea, Rikka saw Yuuta in the past as DFM and was inspired by him to become a chuuni because it looked cool to her and as a way to get away from the pain of her father's sudden death.
Rikka watched Another.Well, it makes sense.
Rikka is Mei Misaki's long-lost twin sisterLet's see, both are brunette, fair-skinned, heterochromic with a red right eye and a green left eye plus wearing the same kind of eyepatch, as well as wearing a similar school uniform. The only thing distinguishing them is that Mei wears the eyepatch over her left eye whilst Rikka wears it over her right eye.
Rikka is related to Okabe Rintarou.Maybe chuunibyou runs in the family.
When Rikka takes off her eye-patch, she really sees everything that the audience sees, and therefore she truly believes that magic exists.The way that Rikka reacts to some of her delusions implies that she is actually seeing them instead of just imagining them, and therefore she really does believe that she is fighting in a magical environment. In contrast, during episode 9, she is visibly surprised and confused when the environment around her doesn't change.
Yuuta and Rikka are reincarnations of Lelouch and C.C. had they lived much happier, healthier, and chuunibyou-filled lives.
Touka is wearing colored contacts like Rikka is in order to change her eye color to red and invoke the Red Eyes, Take Warning trope.To be honest, her eye color doesn't make sense any other way. Plus it does help with her whole Aloof Big Sister and Aloof Dark-Haired Girl look.
Obligatory Haruhi Suzumiya-related WMGHaruhi Suzumiya is a chuuni. Heck, the whole series could easily be interpreted as such.
Chuunibyou are Wild Mass Guesses given human form by The Powers That Be.
All anime heroes ever have just been Chuunis
Poor Homura Akemi was so far into it......that she expended most of her days and energy trying to prevent her best friend from, ahem, contracting the "disease", and chasing away a pale-skinned, frilly-haired chuuni girl (Mitakihara's equivalent of Dekomori) who was trying to lead her friend down that road.
Yuuta, Houtarou Oreki, and Makoto Tachibana from Free! / Swimming Anime are related, possibly cousins
Rikka Takanashi is related to Yomi Takanashi.