These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
The fandom dropped Tsumugu/Kinue like a hot potato, when episode 17 revealed them to have been siblings, instead of just colleagues at Nudist Beach.
There was a mixed reaction for Satsuki/Ryuko: the revelation that they're sisters made the ship stronger for some people, while others abandoned ship because they thought it was squicky, or because they preferred a sisterly relationship instead of a romantic one.
Alternative Character Interpretation: The finale has caused a lot of bickering over whether any of the ships were made canon. On one hand, Mako asks Ryuko on a date and straight up kisses her; however, due to cultural and linguistic differences in Japan, taking someone out on a date isn't necessarily romantic — in Japan, saying that you're on a date can just mean hanging out with a friend, though most proponents of this explanation tend to ignore the possibility of Mako proposing a date in the non- platonic sense. Then, Gamagoori is shown with a bouquet of flowers during the epilogue, implying that they're about to confess to someone — very likely Mako — but the episode ends without showing who they gave them to, if they successfully make their intentions known, if that person fully accepts the gesture or not, or even if the flowers were meant to be given romantically.
Angst? What Angst?: Ryuko got over herself pretty quickly after the Junketsu incident, which involved Junketsu being sewn onto her skin, her being Mind Raped into becoming a loyal servant of Ragyo, likely being molested by Nui and Ragyo, and coming dangerously close to killing her friends. What makes this particularly jarring is that the last major bombshell that was dropped on her (the fact that she's a Humanoid Abomination and that Ragyo is her mother) caused her to have a serious Heroic BSOD and subsequently cling to the Jerkass Ball.
The final battle may be bit of a disappointment for some. Nui doesn't go down fighting, but kills herself to fuse with the Primordial Life Fiber and give Ragyo a further power-up. Then we have Ragyo herself, who is not defeated with some awesome final attack, but by absorbing her ability to control the life fibers, rendering her powerless — at which point she too decides to kill herself.
Arc Fatigue: Probably the biggest criticism of the show is the amount of time spent on Filler, despite the apparent plot going on. It's not until episode 16, and the origin behind the Life Fibers being revealed, that the plot really goes anywhere.
Awesome Ego: Satsuki definitely has truckloads of this.
On the epic side, there's Ragyo's theme, "Blumenkranz"note German for "floral wreath" or "floral crown", sung in heavily accented yet near perfect German; Satsuki's theme, "鬼龍G@キLL"; and, obviously, Ryuko's theme, "Before my body is dry". Bonus points to the latter, because its full lyrics are a dialogue between Ryuko and Senketsu, which sums the series' spirit and themes pretty well.
The first half of "斬LLLア生LL" is basically an orchestral version of "Before my body is dry", and it is no less awesome than the original.
For a change of pace, there's Mako's theme, "Light your heart up", which performs exactly as advertised (and is a tremendous Ear Worm as well).
And then there's Inumuta's and Sanageyama's theme, "犬Kあ3L", which in Aikuro's opinion happens to be the perfect song to strip and strike poses to. The second half is also Sanageyama's theme, which is funny as he spends more time naked than his Elite Four brethren.
A song like "Till I Die" could come across as narm if it were done differently, however this time around they got it just right.
Badass Decay: Tsumugu started off strong, defeating Ryuko and three school clubs all by himself, but in almost all his subsequent battles, he is either ridiculously outmatched or even relegated to Plucky Comic Relief.
Nui is either really funny and cutely evil, or a loathsome dog-kicker with no further motives. Even her leitmotif includes the kanji for disagreeable. Ironically, Nui herself would be more than happy with either opinion of her: love and hate are interchangeable in her view.
Ragyo Kiryuin became this as she got more prominent. Fans either love the fact that she's such an over the top and camp villain, but still manages to be a credible threat and a repulsive person you wanna see die, or hate her for being a shallow, pretentious villain with a generic motive with no justifiable reasoning behind them beyond just being evil, and her molestation tendencies are creepy Fan Disservice.
The fact that both characters died on their own terms despite their horrible actions also left a sour taste in people's mouth.
Broken Base: The excess fanservice has created a large divide between the watchers of the show. There is the camp that likes it and think it fits, considering the creators have worked on other shows that had large amounts of fanservice; there is the camp that tolerates it for the other over-the-top and enjoyable aspects of the show; and there is the camp that absolutely hates it and thinks it exemplifies anime's nasty reputation of being sexist, and refuses to watch the show because of that. And let's leave it there.
On another level is the heated debate over those who feel that the early characterization of Satsuki and the Elite Four as brutal tyrants who oppressed the weak and put down dissenters with uncalled-for force got blatantly white-washed when they switched over to the protagonist side, with Ragyo's overblown sexual abuse and being a one-dimensional Omnicidal Maniac that wants to blow up the earth, being a hasty and clumsy attempt to shock the viewers into discounting Satsuki's earlier faults to that end, while others defend them on the grounds that they did what they had to do.
This argument actually stretches back farther than that: people were seriously claiming that Satsuki was completely justified in all her actions back during the first act, before we saw ever learned of her Freudian Excuse or her being Good All Along.
Satsuki and Takarada. While the two seem to have been acquainted in the past, there is no romantic tension between them at all — aside from the fact that he thinks she's hot — and they haven't interacted since. Hilariously, most art of the ship has Takarada as a Casanova Wannabe, completely failing to woo a disinterested Satsuki.
Nui and Iori, which has practically no basis beyond the fact that the two are both tailors for their respective sides.
Gamagoori and Tsumugu have barely interacted with other, but have a decent number of fans shipping them together because of their Bara Genre appeal.
After the ending Nui and Nonon has started to pop up as a form of Pair the Spares. Since Nonon doesn't get much conformation her love is requited and Nui's defiantly wasn't.
Everything that Nui Harime says and does. She admits to killing Isshin Matoi, and then has the gall to proclaim that hate is the same as love.
Anyone trying to explain Aikuro's "retirement" will inevitably find themselves saying that he exposed himself in front of a young boy. Bear in mind, he's been posing as a teacher. Depending on who you ask, the whole scene is either horribly offensive, or funny enough to keep you laughing for about 5 minutes straight.
Designated Protagonist Syndrome: With such a large and bright cast of secondary characters, its not too surprising to find fans of them than either Ryuko or Satsuki. Of course,Ryuko and Satsuki are both considered the most popular characters on a few select polls, so naturally this isn't universal.
Speaking of those two, some feel this way towards Ryuko compared to Satsuki, especially during the second half of the series, and feel that the later's character was more explored than Ryuko. The fact that in episode 20 where Ryuko has a brief Face-Heel Turn, and Satsuki has to become The Hero and don Senketsu probably helps with these sentiments.
Ear Worm: Ryuko's theme "Before my body is dry" and it's opening line: "Don't lose your waaaaaaay~!"
Oh boy. While the series has been well received for the most part, there are "fans" who take the "Trigger saved anime" statements to heart, swear that Kill la Kill is some type of revolutionary achievement, and get pretty defensive when one disagrees with them. Basically, it's the Gurren Lagann hype all over again.
There's the mass amounts of contention on who's the better character between Ryuko and Satsuki, each side trashing the other for pretty petty reasons.
Satsuki and the Elite Four committed multiple atrocities and abuses of the people in their power in the first half of the series; trying to pint this out in most forums will get you screamed down about how it was all an act on their part and how dare you deny their complete heroism.
Fanfic Fuel: A rather funny example from episode 21: Mako tells Aikuro that she was able to remember Satsuki's plan so well because Satsuki had written every detail on her hands. Cue fan artists making a very intimate scene of Satsuki writing the instructions on Mako's hands.
There are Japanese fanartists who feature Sanageyama and Ryuko with konjac because of the first drama CD where Sanageyama asked Ryuko test questions on nothing but konjac.
A darker and more intriguing incident is the rise of the theory that Mako was replaced, or even possessed, by Nui at some point in the final battle, born from the observance of a number of rather sudden visual and behavioral changes. A detailed post on the theory can be found on Tumblrhere, but be wary of major spoilers!
There's the question of what exactly happened to Rei after Senketsu separates her from Shinra-Koketsu.
Fans of Mako and Gamagoori seemed to increase with every episode. The constant hint-drops in later episodes certainly help.
Inumuta and Iori is probably the biggest yaoi ship in the show, due to the fact that the two of them are the most physically delicate male main characters in the show, and the fact that Houka is literally the only person that Shiro interacts with in a friendly way. A comment by the staff jokingly shipping them also added fuel to the flames.
Ryuko and Satsuki. Satsuki's Junketsu is referred by her mother as her "wedding dress", while Ryuko's Senketsu is mostly black, which is the common color of the groom's tuxedo. In their first major fight, they even shove their chests against each other (5:58). The reveal that Ryuko and Satsuki are actually sisters hasn't stopped some people from still shipping them. However, they eventually stop being enemies altogether as the series goes on.
Nui Harime lives by this paradigm. According to her, the more you hate someone, the more you're able to love that someone. Keep in mind that she seeks to be hated by everyone, which means that she's flirting with everyone.
Growing the Beard: While the series proved to be very entertaining from episode 1, there was not much interest in regards to the plot, but more about the action scenes and the animation. Come episode 11, with Nui's debut and the revelation of what happened to Ryuko's father, along with the plot becoming more serious, resulted in people getting more attached to the story.
After episode 16 and the bath scene, Ryuko's taunt from episode 3 about whether there is anything "pure" about Satsuki seems much less amusing.
Ryuko being afraid of needles was hilarious, but when episode 18 explained why — that she was a victim of grotesque medical experimentation — it stopped being funny.
Hate Dumb: There's definitely some overly-sensitive people who treat the fanservice as if its existence instantly makes the show the worst thing in existence, acting as if rampant fanservice isn't present in any other anime and judging the show solely on one factor.
The whole "losing dignity by wearing Junketsu" part Satsuki says is hilarious if you take into account her voice actress previously voiced Cattleya, who is notable not only for her Stripperific outfit, but also because she's a Shameless Fanservice Girl. Even more hilarious, in a meta way, is the fact her voice actress is also a former porn actress.
The beating Nagita got from the Disciplinary Squad looked pretty funny. It gets better when it is revealed that Nagita was Nui all along, and the Disciplinary Squad guys were actually dolls she controlled. Nui was actually beating herself up in a hilarious way to give credence to her little manipulation stunt.
Idiot Plot: Episode 4. All the drama exists because Mako's mother has to clean Senketsu so Ryuko is unable to wear it.
Incest Yay Shipping: Satsuki is commonly shipped with her own mother, Ragyo, and her sister, Ryuko.
Inferred Holocaust: The casualties of Satsuki's military campaigns and the frequent torture and execution victims of her totalitarian regime.
Iron Woobie: Ryuko. Every known member of her family has either died under mysterious conditions or tried to kill her several times. She was faced with abuse for most of her life, was without either of her parents by the time she was a middle schooler, and had no family or friends until the events of the show. She's spent her whole life moments away from getting what she wants. This is what has driven her on over seventeen years on earth. She couldn't escape this even in her moment of triumph against Ragyo, since defeating them ended up costing Ryuko one of her first friends.
Satsuki. She may be the head of a fascist dictatorship that has claimed much of Japan and razed much of Kansai, but her mom is — quite frankly — a walking freudian excuse of the highest order.
Rei and Nui, who are used as completely disposable pawns by Ragyo, and they both have accepted this sad truth◊. Points off for, unlike Satsuki, doing nothing to change this — and in Nui's case, flat-out enjoying what she does as Ragyo's puppet, with some exceptions◊.
There are two camps: those who go for the shameless fanservice or those who come for over the top, insane and nonsensical reputation of its creators. Those who stay find that one can't exist without the other.
And then there are fans who watch the show for Nui's antics.
Mako for Ryuko, which sometimes goes beyond fangirling.
When Ryuko's nipples are nearly exposed during the official fight against Gamagoori, Mako gets a nosebleed!
Senketsu points out how Ryuko calms down from a fight when she watches Mako being adorable.
When Aikuro freezes Mako by hitting her "freezing pressure point" with a pin, Ryuko quickly tells him to unfreeze her because "talking to her makes me feel a whole lot better than talking to you".
Hell, Mako's theme song, "Light your heart up", is basically all about how much she enjoys being Ryuko's friend. And the lyrics of the second ED, "Shinsekai Kōkyōgaku" ("New World Symphony"), are also about how much Mako cares for Ryuko.
Really, Mako has frequently shown herself as the most capable and reliable of motivating Ryuko, and has snapped her out of an earlier Heroic BSOD, saved her from the Ax-CrazyHeroic RROD that caused her and Senketsu to become something horrifying, and was able to break her out of a lot of her brainwashing in episode 21. Her method for doing this can be described as tearing off her clothes and entering her.
Mako asks Ryuko out on a date towards the end of the final episode — which includes kissing Ryuko twice — and the credits show them going shopping with Satsuki.
Jakuzure's relationship with Satsuki has hints of this. She's the first one to refer to Satsuki affectionately, swore to always hold her hand while in kindergarten, and hasn't left her side since. She's also the only person Satsuki calls by their first name.
Being subtle is not in Nui Harime's nature. She flagrantly flirts with Satsuki, even though it seems to make her annoyed; it's rather telling that the ones who actually get riled up by this are Gamagoori and Jakuzure. Then she starts putting the moves on Ryuko, claiming that hate and love are interconnected, and thus, by hating her, Ryuko loves her.
In episode 20, Nui claims that she and Ryuko are "soul sisters", by virtue of being life fiber-infused human beings, and that she is the only one Ryuko can possibly understand and relate to.
And in episode 21, Ryuko gives her a pretty deep kiss that leaves Nui blushing.
Ragyo feels up her progeny in nearly every scene they share. However, this is played for serious Squick, rather than fanservice.
Gamagoori and Tsumugu are rather popular with gay male fans. Their status as Mr. Fanservice certainly helps.
Jakuzure for gay female fans. There are quite a few female fans who declare her the most attractive character in the series, for instance.
Like You Would Really Do It: Subverted — once in episode 12, and then played straight in episode 13. Apparently, Senketsu has multiple spots where you'd have to hit him to rip him to shreds, unlike goku uniforms. Thus, in Ryuko's first fight with Nui, her Finger Poke of Doom has no ostensible effect. Not many people really thought Senketsu would fall apart during a fight scene with an Outside-Context Villain, at the climax of the season... except that he gets cut to pieces by Nui in episode 13 anyway. He spends the next few episodes getting patched up by Ryuko, to whom Satsuki left his eye-scarf.
Nui is an extremely unusual case, where her fans actually started hyping her badassery up a lot more afterher first complete defeat. The reason behind the surge was a combination of multiple factors; the personality change she went through immediately afterwards made her less obnoxious and more intimidating, the fact that her grievous injuries did little to hinderher willingness to fight or her ability to keep working on REVOCS' master plan, and her defiance of the mockery she is subjected to by both friend and foe afterwards inspiring her fanbase to raise their voices to counter the vast majority of viewers calling out Take That, Scrappy! That Nui recovers completelyin the following episode adds even more fuel to this memetic status. Love her, hate her, or both: either one, you just can't keep her down.
Mako, while donning her Fight Club President Uniform. Half of the batshit crazy stuff in episode 23 wouldn't be possible if not for her, and Iori even notes that her power level exceeds 9999. Vegeta would be proud of her.◊
What more than a few people think of Senketsu, considering the way he takes off Ryuko's clothes and, for lack of a better term, "forces himself" on her afterwards. And this is the first thing he does on-screen. This view has died down episodes after, though, as Senketsu since hasn't really done anything forceful, and is shown time and time again to care deeply for Ryuko's welfare.
After her formal introduction, Ragyo Kiryuin became this. Almost all of her scenes have her doing something extremely perverted, mostly to her child Satsuki.
After Ryuko and Satsuki were revealed to be sisters, the fandom had a field day, turning the latter into a full on siscon for the former. It led to some hilarious results.
Ryuko, Satsuki and Ragyo in their Stripperific kamui outfits. Clear as day.
Aikuro. Being subtle is against his nature. Come Valentines Day, most Kill la Kill jokes involved him and his shiny parts.
Jakuzure. Let's just say that there are many ways that one can twist her musical themes into something else.
Moral Event Horizon: From a narrative standpoint, Ragyo Kiryuin crossed over it during episodes 17 and 18, where she gleefully offered a stadium of innocent people to the Life Fibers as food, which luckily didn't succeed; delivered a completely and utterly brutal beatdown to Satsuki. However, the aforementioned events are mere Kick the Dog moments when the exact point where she crossed this line is revealed in a flashback - the moment when she casually disposed of her newborn second daughter (that she didn't even give a name to) when experiments on her failed. Her actions in episodes afterwards simply serve to dig her hole even deeper.
Misaimed Fandom: Satsuki and the Elite 4 had tons of fans rooting for them in the first half of the series... Ya know, when they were the antagonists who upheld a fascist government and silenced anyone who stood up to them. They do perform a Heel-Face Turn, but fans like to ignore the blatantly morally questionable things they've done.
The satisfying clack of Satsuki's — and by extension, Ragyo's — boot heel just before she begins a speech.
Most of the wacky sound effects featured during Mako's own speeches, especially the little "Hallelujah!" that plays when she begins one.
The sound Bakuzan makes when it pierces Ragyo's chest. There is something incredibly satisfying in how that sound cuts off Ragyo's speech.
DON'T LOSE YOUR WAY!Explanation The ever-so-famous line from Ryuko's Leitmotif, "Before my body is dry". It is the first thing one hears when Ryuko kickstarts Life Fiber Synchronize with Senketsu.
And by extension, the orchestral version of that riff, from the first half of "斬LLLア生LL".
Gamagoori's mad laughter is awesome, but especially so in episode 24, where he was supposedly dead and the other Elite Four were in a stalemate with Nui; but then that laughter echoed through, and all was right with the world again.
The ridiculous designs of the kamui can also be seen as a little too Stripperiffic to be taken remotely seriously, despite their use in fairly awesome fight sequences. See also Fetish Retardant above.
Ryuko wearing Junketsu would be a lot easier to take seriously if it weren't for those weird... leg-skirt things. It's possible that the big poofy pant legs are supposed to resemble hakama, but that doesn't stop them from looking outright silly.
Ragyo's abusive treatment of Satsuki, while intended to be shocking and make her come across as a bad guy, seems to also be producing this effect on some viewers lately; especially in episode 19, where she simply caresses and then spanks Satsuki several times, and not particularly hard, all while cackling maniacally. Perhaps there's some sort of sadomasochism fetish involved.
Nui gets her arms cut off. Cue the Monty Python and the Holy Grail jokes. Later on, her angry "tailoring" of Shinra-Koketsu looks more like she's chewing on red meat than sewing something with her mouth.
Gamagoori's supposed death in episode 24 is hard to take seriously when Mako is spouting comical amounts of cartoonish tears over it.
Any time Mako cries during a serious scene, though to a lesser extent than the above example.
The final battle between Ragyo and Ryuko becomes increasingly hard to take seriously, when Ryuko and Senketsu start to repeatedly assert that "humans are humans and clothing is clothing", and that the two of them "are neither human nor clothing". It Makes Sense in Context, but the subject of the phrases combined with the overblown conviction with which they say, it makes it impossible to listen to with a straight face the first time, let alone the fifth. When Ragyo gets fed up and just starts yelling "what is this nonsensical garbage you keep babbling about", quite a few viewers found themselves sharing that sentiment.
Kamui uniforms derive their power from the blood of their users. Viewers who are Afraid of Needles and have experienced having their blood drawn may feel themselves fainting at the whole concept.
Sukuyo's mystery croquettes. Yuck!
The entirety of episode 12, after Ryuko overwhelms Senketsu with her rage and they morph into a hideously deformed berserk hybrid. There's blood spraying literally everywhere, Ryuko and Senketsu are both screaming in savage agony, and the extent of the damage they take before they finally go down is almost sickening.
The end of episode 18, where Ragyo rips Ryuko's heart straight out of her chest, still connected and beating! And then episode 19 ups the ante when Ragyo holds an entire conversation with Ryuko while still holding the beating heart; when Ryuko finally gets out of Ragyo's grip, her heart is briefly seen dangling by its arteries before being sucked back in her chest, as Ryuko is looking in pure horror at just how inhuman her body is.
This is repeated in episode 20, with Nui holding out her own heart, coloured a rather unhealthy-looking blue, but it luckily has less focus.
Episode 24 has Ragyo ripping out her own heart and crushing it in her bare fist, all in glorious, nauseous detail.
The end of episode 21. Ryuko rips off Junketsu, which had been sewn to her body, and ends up covered in blood from literally head to foot.
No Yay: The show is heavy on the sexual imagery, and some of it can get seriously disturbing.
Any ship in which Ragyo is involved, largely because her interests lie exclusively in getting what she wants. All the Parental Incest doesn't help, either; neither does the fact that she's a Humanoid Abomination. In fact, it's hard to think of many ways in which Ragyo's unsubtle advances on the rest of the cast aren't creepy.
Ditto for Nui, who — bar the mental instability — is pretty much Ragyo's frilly pink marionette.
OT3: There are a lot of these; mostly revolving around Satsuki, Ryuko, and Mako, which is a popular ship as well with Nonon often added, especially since the final episode has the three going on a date together.
Nagita was Nui all along. And in his brief screentime, he'd quickly managed to become a very developed, sympathetic, and seemingly-trustworthy ally.
Imagine, you're exhausted and have to be extracted from a war zone by a chopper. Then, the pilot of the chopper turns out to be the last person you want to be carrying you to safety...
What if your clothes were actually embedded with an alien thread, that would eventually consume you, along with the entire planet?
Rescued from the Scrappy Heap: Some people who didn't like Nui softened up to her after she lost her arms in episode 22. It helps that she made a fairly cool comeback in the next episode, which came off as genuinely badass rather than cheap.
And then in the grand finale, she defies expectations and offs herself to power up Ragyo, which was such a psychotically ballsy move that it won her even more respect.
After the reveal from episodes 17 and 18, the craziness of Honnouji Academy in the earlier episode makes sense given its actual goal of raising an army to destroy Life Fibers.
With this reveal, it becomes pretty obvious that Satsuki was training Ryuko to help in her rebellion against Ragyo. This is confirmed in episode 22.
If one were to rewatch the second fight between Fukuroda and Ryuko from the first episode, they'd notice that "Blumenkranz", Ragyo's theme, starts playing once Ryuko's cloak comes off. Considering the revelation in episode 18, this may have been intentional.
The wedding dress from the first ED makes a reappearance in episode 20, in Ryuko's implanted fake memories.
Rooting for the Empire: There is a sizeable contingent of fans who watch the show for Satsuki and the Student Council. Though, in episode 17, they became the good guys...
Sacred Cow: Satsuki and the Elite Four, specifically their status as good guys. Huge portions of the fanbase will angrily write off anyone who tries to argue that some of their actions in the beginning were not performed in good sense, and that they still have a lot of past crimes to answer for.
Ship Mates: Ryuko/Mako fans often also pair Satsuki/Jakuzure (or, less commonly, Satsuki/Gamagoori or Satsuki/Sanageyama), while Ryuko/Satsuki fans are the natural ally of Mako/Gamagoori shippers. Inumuta/Jakuzure is also common for fans of Satsuki and anyone other than Jakuzure.
Some people just took the third option and ship Ryuko, Mako, and Satsuki, especially after the epilogue of the final episode. Mako/Gamagoori shippers are a bit ambivalent about the whole thing, considering the ambiguity of their ship.
In the second to last episode Ryuko and Nudist Beach manage to destroy the Primordial Life Fiber, seemingly putting an end to Ragyo's Evil Plan. Sure enough, Ragyo has a few tricks to ensure her plan gets back on track until the end of the final episode.
In practically all their scenes together, Ragyo touches her progeny in a way a parent should never touch their children.
The scene where Ryuko undoes Ragyo's mind-control threads wrapped around her brain, by reaching into her skull to yank them out.
To say nothing of her having Junketsu grafted onto her body, or her tearing it off with her bare hands, an act which covers absolutely everything in a fine spray of blood.
Take That, Scrappy!: Nui losing both of her arms, screaming in shock upon realizing that she cannot recover them, and having a complete breakdown as a result, made most of the fandom happy.
Hilariously, both of these are undone in the very next episode, leaving the fandom feeling Trolled. Then again, it's Nui, so that feeling is to be expected.
They Wasted a Perfectly Good Character: A disproportionate number of examples for such a short and neatly tied up story, the fault is largely because of the relatively large and diverse pool of secondary and tertiary characters whom all have colorful personas and (at least initially) imposing presence, but who are largely reduced to background or even one-shot roles. The members of the Kiryuin family are the only ones who actually move the plot along, and one the backstories of Ryuko, Senketsu, Satsuki, and the Elite Four are given any sort of information.
Tsugumu Kinagase established himself as a certified badass when he gave Ryuko not one, but two curb stomp battles in his debut. A lot of fans were interested in his backstory and hoped he would contribute a lot to the series. Unfortunately, he's relegated to being a jobber who can't catch up, while the younger heroes continuously get stronger with their upgrades.
Rei Hououmaru. She seemed to play The Dragon to Ragyo along with Nui, but literally nothing about her is explored and she accomplishes next to nothing as well. She gets absorbed into Shinra-Koketsu with little to no fanfare, and even when she's freed, it's treated like an afterthought. Her fate at the end of the series is also not disclosed, either.
Brainwashed Ryuko could count towards some. A lot of people were hoping that Trigger would use them in an interesting way, but ultimately the character's situation is resolved in the very next episode, in almost the exact same way beserk Ryuko from episode 12 was, leaving fans wondering what was the point of establishing such a character in the first place.
Ragyo's characterization is barely explored. Some feel her character to be the weakest part of the series, due to her lack of motivation beyond her evil plan, which itself barely amounts to more than end humanity via the Life Fibers.
Junketsu is presented as an antagonistic counterpart to Senketsu, but doesn't speak, very little of its background is explored, and is absorbed to power up Senketsu without a word. It is ultimately treated no differently than a Goku Uniform.
Kaneo Takarada is the Student Council President of his own highly effectively militarized high school, scion of a shipping business that rivals the Kiryuin Conglomerate's economic power in at least Japan, is the main finance and weaponry supplier for Nudist Beach, knew Satsuki as a kid, and is one of the only people ballsy enough to defy and challenge Satsuki and the Elite Four, even after being beaten down and humiliated by Sanageyama. Also the American viewership idolizes him. With all these credentials, you'd imagine he'd be an incredibly effective and charismatic commanding presence in the later battles. Nope, he's captured in his second episode, rescued off-screen, and just gets a half-minute cameo during the build-up for the penultimate confrontation.
Iori also gets no character focus or backstory, and never enters the battlefield either as an opponent or an ally, despite being the creator of the Goku Uniforms, being part of Satsuki's inner circle, and the nephew of her Parental Substitute butler.
Aikuro is the apparent leader of Nudist Beach after the death of Isshin, but we never get to hear a word of his backstory or motivations.
A sizeable contingent of fans are disappointed by Mako's decision to have Ryuko simply destroy her two-star uniform, which is monstrously powerful, and not to mention incredibly awesome, instead of keeping it and helping Ryuko in the fight against the Kiryuins. She actually gets it back at the end of episode 22, however, much to the delight of said fans.
The reaction towards Nudist Beach wasn't very good either. People had come to expect a small band of badasses in the style of Tsugumu, instead they got a bunch of faceless red shirts in silly looking mechs.
When Senketsu was cut up and put into a bunch of upgraded goku uniforms, it was the perfect chance to bring back some of the club presidents, at least one of whom is a pretty big Ensemble Darkhorse, especially considering that the student council regained their ranks right after the Naturals Election. Like Mako above, however, they did end up making a minor comeback in episode 23; while minor, it was enough to appease their fans.
Some fans, especially those of Satsuki, felt that Ryuko's forced Face-Heel Turn in episode 20, which was negated the next episode, was a perfect chance to make Satsuki The Hero, and better show her and Ryuko's Character Development especially since Satsuki is much more involved against Ragyo than Ryuko is at this point.
Viewer Gender Confusion: When the Sewing Club President Iori first appeared in episode 2, viewers became enticed by this attractive new blonde-haired figure... and then "she" spoke.
Villain Sue: Nui Harime, up until around episode 18. She's under direct command of Ragyo, who lets her do whatever she wants, on the grounds that she's an "artiste". That, and her motives pretty much revolve around getting as many people to hate her as possible — which she was largely successful at doing. Despite not even wearing a goku uniform, she was more powerful than much of the cast—neither of these were explained until episode 20. In her first three episodes, she...
The Woobie: Senketsu, as of episode 19. The poor guy's closest friend now hates him and views him as a monster, then left him lying in the rain devastated. And this is after he risked his life dragging her to safety, after Ragyo injured her, and sat by her side the entire month she was in a coma. Episode 21 takes a step further with him being trash talked by a brainwashed Ryuko. Episode 24 takes it farther, with him sacrificing himself to save Ryuko, whilst telling her that she is free to wear clothes that are cuter than he is. And this is the last thing he ever says to her... poor guy.
In the Aniplex English sub, the name of an event in which the Student Council were booted from their seats and expected to fight their way back to the top went from a pun on 解散総選挙 ("snap election", read as kaisan sousenkyo) note 壊惨総戦挙, lit. "broken, cruel general battle election", read the same way to one on natural selection,note "The Naturals Election" which went along with the implication that only the fittest would survive to form a new council.
Rather than try and translate the pun on kiru ("to wear", though as it's written, could be read as "Kill"), Trigger gave the show's Chinese simulcast the title The Girl Who Cuts Cloth. The character used for "Cloth" could also translate as "Dual-Wielding."