Back in middle school, Yuuta was himself a victim of "Chuunibyou Syndrome", fancying himself as the "Dark Flame Master", a goth guy clad in black who can wield dark-purple flames. Nowadays, though, he'd rather disassociate himself from it, which caused him to become stigmatized, thus come high school he moves away far enough to where his old classmates cannot find him. But his past still comes back to haunt him, one way or another, when he meets a girl still suffering from chuunibyou... who proceeds to blow his cover.
All the Other Reindeer/Eating Lunch Alone: The direct consequences of his overblown middle-school fantasies. Thus he considers Makoto's offer to eat lunch with him as a good start to a far more normal high school life.
Bandage Dude: Used to wrap his arms as part of his "Dark Flame Master" persona.
Chekhov's Gun: Yuuta's collection of items related to his "Dark Flame Master" persona, which he originally planned on throwing away come tenth-grade, turn out to be useful whenever he has to distract and/or keep Rikka and Sanae preoccupied.
Cloudcuckoolander: Used to be one during his "Dark Flame Master" days, going so far as to, in several Lite episodes, bring an unconcealed rifle out in public while accompanying Kuzuha's friend (but at least he's sensible to hide it in the presence of a cop).
Innocent Cohabitation: Rikka moves in after his mother moves and Rikka's grandfather didn't hold the apartment.
I Just Want to Be Normal: Sincerely hopes to leave behind his middle-school weirdness behind and spend his high school days in relative normalcy, by transferring to a high school far enough that no one from his old school would attend. He accomplishes that for the most part, but then came Rikka.
Would Hit a Girl: Ready to smack Rikka in the head — or any girl for that matter — whenever her delusions or mean-spirited selfishness like in the case of Shinka run wild. In episode 2 of Ren, he actually spanked Rikka for using up nearly all her (pretty high) allowances just to buy a pair of binoculars.
A strange girl who wears a medical eyepatch over her right eye and has just moved into Yuuta's apartment building upstairs with her older sister Touka. Unlike Yuuta, Rikka indulges in her delusions even well into high school in the form of "The Wicked Eye", a goth-loli who wields a weaponized umbrella.
Adorkable: As a result of her small and cuddly appearance awkwardly contrasting with her delusions of grandeur.
Gets broken again at the end of episode 10 where the last support she has for her delusions, Yuuta, suddenly turns on her and tries to make her face reality right before they were supposed to perform at the school festival and not even a day after they had confessed to each other.
Clingy Jealous Girl: She starts to exhibit these traits once Satone, an old friend of Yuuta's, shows up in season 2, and gets a little too friendly with him.
Cloudcuckoolander: Looks at the world through the lens of her fantasies in a near-constant basis.
Everybody Hates Mathematics: Rikka is frankly terrible at it. While she lucks out in the anime due to the class average being lower than usual, in the light novels she has to retake the exams at least thrice, and passes none, with her highest being 30/100.
A beautiful, chuunibyou-hating girl in Yuuta's class who is also a transferee. In the anime, her attitude is explained as the result of her desperate attempts to erase all traces of her past as a chuunibyou herself, having went by the name "Mori Summer", a medium and writer of the "Mabinogion", her journal of faux-philosophical rants currently in Sanae's possession.
Academic Alpha Bitch: In the first episode of Ren, her classmates said Dekomori's grades were even better than she is. This implies her grades are also extremely strong, just not as high as Deko's.
Alternate Character Reading: The kanji of her given name can also be read as "mori natsu" ("forest summer"), thus her chuunibyou alias "Mori Summer" in the anime. The light novel version of Mori-samajust took the first kanji.
Berserk Button: Any mention of chuunibyou, given her past as one, as well as (in the anime) Sanae's insult to her as a "Fake Mori Summer".
Bitch in Sheep's Clothing: She's not exactly a bad girl at heart, but she can get pretty snippy and mean every time the issue of chuunibyou is taken up because she's just that desperate to erase all traces of her own past as one.
The Bully: Towards anyone she regards as her moral inferiors.
Cassandra Truth: No matter what she tries to say or claim, Sanae absolutely refuses to believe she was "Mori Summer".
Old Shame: In-Universe — like Yuuta, Shinka resents her past life as "Mori Summer". Unlike him, however, she's not as good as him when it comes to facing the fact that her past will always haunt her.
Really 716 Years Old: Claims her "Mori Summer" persona to be this, as well as the "oldest mage in the world".
Red Baron: Mori Summer in the anime, and Mori-sama in the novels.
School Idol: Downplayed. She is without dispute the class idol, but nothing was mentioned beyond class 1-4.
Shaggy Dog Story: No matter how hard she tries to purge it, "Mori Summer" will always live on in Sanae's delusions. And to add insult to injury, Sanae won't even acknowledge Shinka as the real deal because she doesn't match up to her "Mori Summer" image. At least until episode 4 of Ren.
Anime-exclusive character. A sweet kid and Yuuta's upperclassman who's quick to fall asleep.
Alternate Character Reading: The kanji for her surname is written as "五月七日" (May 7) — Tsuyuri being a festival that falls on that day. In Episode 2, Yuuta did mispronunce that as "Gogatsu-nanoka", and has to be corrected.
Anime-exclusive character. A kid from the school's middle-grade department. Like Rikka, whom she met on the internet, Sanae also suffers from chuunibyou. She takes on the form of "Mjolnir Maul", a mid-range fighter who uses her long bola-resembling twintails to fight - which more often than not serve as hindrance rather than help. In the world of delusions, she then "switches over" to a gigantic hammer.
Badass Adorable: Like Rikka, the "badass" part is debatable, the "adorable" part undeniable.
Clingy Jealous Girl: Gets upset in episode 13 during the Christmas party because of the fact that Rikka and Yuuta are dating, and is a little drunk from chocolate cake. And early on in season 2, doesn't take it too well that the two are living together due to Rikka losing her apartment. She also gets upset at Satone for getting too close to Shinka in episode 11 of season 2.
Cloudcuckoolander: She has shades of this from time to time, but is actually quite intelligent as well.
Covert Pervert: She goes beet red when wondering if Rikka and Yuuta are doing anything naughty, as suggested by Shinka.
Crazy-Prepared: Well aware that the Mabinogion she's keeping can be destroyed, so she keeps copies. Online ones, that is.
Ditzy Genius: Despite being so deep in her delusions, she's still the top student in her grade. Yuuta and Shinka were utterly surprised.
Expecting Someone Taller: Refuses to acknowledge Shinka as the girl behind "Mori Summer" because the former was expecting the messenger of love, not the jaded high-schooler desperate to purge her past delusions. Well, until episode 4 of Ren, when she recognized Mori Summer's hand bangle as seen online is the same as the one the latter photographed with Satone.
Genki Girl: Tends to get overly excited around Rikka.
Girlish Pigtails: Which she attempts to weaponize by turning them into bolas, though she usually just ends up getting tangled up in them.
Secretly Wealthy: In episode 12, Kumin mentions that Deko drove them. Cue them panning to a Mercedes-looking car with a stern looking M.I.B. next to it. Then the club goes to her house for a Christmas party in episode 13, and she lives in a really large one...
She Cleans Up Nicely: No one recognizes her, but she actually turns out to be pretty good-looking when she has her hair down and acts like a normal person.
Verbal Tic: Vocalizes the word "desu" to sound like "death"note Japanese can't really pronounce the ending "th," so they vocalize that as "s." The difference between "desu" and "death," is more that of a tone..
She changes to "desu yo" after Yuuta brutally lectures her on reality.
Weaksauce Weakness: Ingesting milk or any milk-based food item will stop her in her tracks.
Butt Monkey: While most of the main characters are unlucky, Isshiki is arguably the unluckiest. For example, the poor fellow's attempts at wooing Kumin with the later never noticing one bit. Even better, when he finally does confess in episode 10, it's on a stage in front of the entire school, unfortunately she was asleep at the time.
While Yuuta will give the girls a smack or chop every so often, when it comes to Isshiki, he pulls out all the stops and just wails on him. It comes to a peak at episode 10, where the poor guy gets kicked in the face, his head slammed into the floor multiple times, and comboed.
This gets even worse in Ren, where he also loses the little relevance he had and everyone forgets who he is.
Hopeless Suitor: Towards Kumin, although that doesn't stop him from trying.
Love Confession: He gives one to Kumin in episode 10, but the latter was sleeping at the time.
Love Letter Lunacy: He gets one at one point, and Shinka seems to verify that it came from a girl. However, due to him dropping his diary on the list of girls ranked by their cuteness, the boys in their class get in trouble with the girls for it, and he takes the blame, partly because it was his notebook, and partly because he wanted to look cool by taking the heat and punishment. As a result of it however, whoever wrote that letter understandably doesn't show up at the meeting place in the letter, although he's instead greeted by all the boys who worship him for taking the blame.
Important Haircut/Traumatic Haircut: He promised to shave his head bald as gesture of apology to Class 1-4 when his girl-ranking book was discovered. Turns out he doesn't want to go through with it, but is pestered by Shinka about his vow. Poor guy isn't happy at all, especially considering he had to deal with being bald for the past three years, and fears he will end up Prematurely Bald like his father. However, said trauma is minimized when Kumin pats his head due to not being able to resist touching his now bald head.
No Sense of Personal Space: At times he gets uncomfortably close to Yuuta. He also laid his head on the latter's shoulder, and immediately earns a couple of hits from it as a result due to Yuuta finding another guy doing that to him incredibly creepy.
Out of Focus: While he never had a lot of screentime in the anime in the first place, he's almost invisible by season 2.
Prematurely Bald: His father suffered from this (completely bald by 35) and he thinks he'd be the next according to his genes.
Genre Savvy: When Rikka attempts to use Gratuitous English as a loophole to have a "fifth" member joining their club, Nanase plays along, and speaks a lot of english as well. However, Rikka is unable to comprehend some of the words the latter uses, so pretends that said split personality went back. And since the "fifth" member isn't there anymore, she says they can't use that excuse to form their club.
Reasonable Authority Figure: She allows Rikka to form her club on the condition that they clean up a room. Although it takes a while due to the girls goofing off more than clean, she upholds her end of the deal and lets them form a club despite not having five human members at the time.
Smarter Than You Look: Of course, being a teacher, she's intelligent, but Yuuta notes that she can be quite cunning, as shown when she plays along with Rikka's delusions while the latter submitted her club formation form for her "Eastern Magical Nap Association".
Anime-exclusive character. Rikka's older sister and a professional cook, with whom she has a not-so-good relationship, owing to the fact that she mostly serves as the serious foil to her insane antics.
Arguably a Deconstruction. Her aloofness results from her inability to handle her sister very well and her own emotional problems. As a result, she ends up hurting her sister more than helping when it comes to her time of need. Even she realizes this herself, and often asks Yuuta for help.
Establishing Character Moment: Her first conversation with Yuuta, she described Rikka's delusions as problematic, forced her to get rid of the cat (to be fair, she has allergies) and blackmails Yuuta into taking care of it.
Jerk with a Heart of Gold: She's abrasive, rude, cynical, and hurtful, but she really does have good intentions. She tries to help her sister, just not in the nicest ways.
Knight of Cerebus: A non-villainous example. Despite being Comically Serious, her arrival is often a sign that things are going to become sadder, as she tries repeatedly to bring Rikka back into reality, however harsh it may be.
Supreme Chef: Rikka may not like Touka much, but at least she appreciates her cooking.
In episode 10, it was revealed she would be sent to "the head restaurant in Italy" for training.
Voiced by: Juri Nagatsuma
Appears in the second light novel and the second season of anime. Yuuta's chuuni friend from middle school who suddenly moved away. Yuuta mentions that she's probably the reason he got infected with chuunibyou. Unlike Yuuta and Shinka, who have been cured from chuunibyou, and Rikka, who is infected but is unaware that she has the disease, Satone is completely aware that she is infected and is loving every moment of it. Her chuuni persona is Sofia Ring SP Saturn the 7th, or Sofia-chan, the Magical Demon Duchess.
Childhood Friend Romance: It's pretty obvious when she shows up in season 2 that she liked Yuuta back in middle school. Especially considering they hung out and did the chuunibyou schtick together. Once she realizes that he forgot a lot about her, such as the arcade token, as well as dating Rikka, she becomes an Unlucky Childhood Friend.
Green-Eyed Monster: Revealed to be her motivation for kidnapping Rikka and forcing Yuuta to play a game with her to get her back.
That only applies in the light novels, however. In the anime, she's perfectly fine with everything. Until episode 10 anyway...
Hopeless Suitor: While she didn't have a chance anyway due to Yuuta dating Rikka by the time she shows up in season 2, she realizes she's fallen into this trope by episode 11 of season 2 after seeing how determined he was to find Rikka despite the latter being sick and still looking for the MacGuffin written in his notebook.
I Want My Beloved to Be Happy: In episode 7 of season 2, she runs into Yuuta and Rikka during their field trip. After some mishap involving a monkey and her lost purse, Rikka sees her giving a coin to Yuuta, and runs off. After Satone realizes Yuuta forgot the meaning of the coin, she then attempts to make her peace with Rikka by claiming that he belonged to the latter, and that she would stay as a chuunibyou, and messages Yuuta so that he could find where Rikka was so they could spend the end of the day together alone.
Love Epiphany: She tells Rikka about the first time she felt hers in episode 7 of season 2. She realized that she was starting to fall in love with Yuuta, and started to see the chuunibyou as foolishness, kind of like how he was at the start of the series going into high school. However, because he was still a hardcore chuuni at the time, she put up with it to be close with him until she moved away. Once she realized that he forgot a lot about her, and that she was inadvertently causing strife in Rikka and his relationship, she decides to gracefully step out.
Love Hurts: In episode 9 of season 2, she feels a tinge in her heart after helping Rikka renew her "powers". And in episode 10, several of the other girls confront her about her feelings towards him at the request of Touka. Then she asks some questions directly to Yuuta, and despite her reassurances of being resilient, his answers seem to knock her off her feet. And just when she thought she got over it, he runs back and offers her an umbrella, causing her to lash out at him and runs off.
What Is This Thing You Call Love?: She suffers from this twice. Once when she and Yuuta were hanging out together, and later on when she moves into the apartment above his where Rikka stayed in the first season. She was somewhat unaware of why she felt this way until Shinka points it out to her, who only suspected it thanks to Touka having a hunch.