Magical Project S's tough Misao Amano is the Shrinking Violet. While she appears to be cheerful, in reality she's hiding her lack of self-esteem— and her loneliness and jealousy which manifest as PixyMisa.
Way before her, Sasami in the Tenchi Muyo! proper. Imagine going 700+ years thinking that you were not the real Sasami, that the real one died when she was four, that you're nothing more than a vessel for a powerful goddess and that, if anyone else found out, there was the humongous chance that everyone would turn away from her.
Allen Walker of D.Gray-Man He's even called out on it by his mentor. When his foster father died, he went into trauma, and had to be taken care of for months. When he finally snapped out of it, he adopted his father's personality. Pre-trauma, he was rude and foul-mouthed. Now, he's somewhat repressed. He hid behind false smiles, and would sometimes claim to be fine when he wasn't. In a message, his master told him to stop wearing the mask of his father, and be his own person if he hasn't lost hope.
Kare Kano is defined by this trope. Both Arima and Yukino are Type A. However, Yukino's version is played for laughs because hers stems from her own narcissism and desire to have people compliment her. Arima's, on the other hand, is played as drama as he tries to coverup his insecurities of that developed from being abused and abandoned by his parents and being considered the Black Sheep by the rest of his extended family.
This all culminates into a relationship between the two, with Arima thinking some...terrifyingly possessive thoughts about his girlfriend who is oblivious to the dark turn his thoughts took.
Mitsuki Koyama, the main character of Full Moon o Sagashite. She acts like a Cheerful Child whose biggest wish is to see the boy she loves again, but it's eventually revealed that the boy she loved had been dead for years and Mitsuki was only pretending he was alive to everyone else, so that she wouldn't have to face that reality.
Yoko Nakajima, the main character of The Twelve Kingdoms, starts out the series as a junior version of this in regards to her home and social life; she reveals later the fear that there was truly nothing inside.
Masane from Witchblade has this to a degree. After losing all her memories in the great quake, and even her old name, all she had to build a new life was her daughter Rihoko. She is constantly saying that Rihoko is the only thing she has and aside from being her mom, there really isn't that much to Masane. Well until she activated the Witchblade and became an Action Mom. As the series progresses, she gets better.
Tohru Honda from Fruits Basket is a genuinely kind and caring person, but has serious insecurities that she hides behind her smile and cheerful disposition to avoid troubling her friends.
Digimon Tamers had a Stepford Smiler in training in Juri Katou. Early on, her main character traits are being cheerful and carrying around an alternatively cute and creepy puppet; later in the series, we find out that she never quite got over her biological mother's death, and everything went to crap as soon as the series' running "joke" happened: for non-fans, Leomonalwaysdies, and this time, he just so happened to be Juri's Bond Creature.
Asakura Ryoko from Haruhi Suzumiya fits this trope more or less. As she acts like a Purity Sue, she keeps a cute, caring and friendly appearance, even when she is about to stab you with her beloved combat knife, or when dying. Since she is an Artificial Human, unable to empathize with humans, it is very likely that it is just a fixed masquerade, thus Type C.
It becomes especially disturbing when you consider that it's likely the only time only time she's really smiling is when she's trying to kill Kyon. She's also, arguably, a deconstruction of both the Stepford Smiler and the Purity Sue. How is it possible to never stop smiling for a moment? To have no understanding of what the expression means.
In the Disappearance movie (spoiler warning, it shows a scene from the film), that smile seems even more sinister than it did before.
It's plainly obvious that the overly optimistic and cheerful Kafuka Fuura from Sayonara, Zetsubou-Sensei is a Stepford Smiler. Even though she hides her traumatic past, some of her classmates are acutely aware of her mask and are mortally terrified of her. It doesn't help that she's secretly stalking Itoshiki-sensei by disguising herself as a college student who lives next door and has been steadily poisoning him with gifts of food...
To say nothing of Anthy. She is initially presented as a demure, somewhat shy and even submissive girl, but by the end of the series it has been revealed that not only has she been living with an unimaginable amount of both physical and emotional pain, but she could even be considered a puppet of the series' Big Bad (her own brother). She's possibly Type A and B, perhaps even Type C.
Utena herself shows signs of being one at times. She was rather depressed in the past to the point of wanting to die after her parents died because she saw life as pointless if all humans eventually die.
Another example, while less extreme, would be Miyako, who has her own fair share of troubles.
Orihime Inoue from Bleach is a very gentle, sweet girl as well as the local Genki GirlBarrier Warrior. Also has huge self-esteem problems, views herself as inferior to the Shinigami, feels troubled because she adores said Shinigami (and specially Rukia) and is in love with Ichigo. Cue to her almost having quite the breakdown in the Arrancar arc... and a full-blown one in the Hueco Mundo arc.
Captain Unohana is a type C. Not only is she the First Kenpachi, she is also just as Ax-Crazy as the current one. She named herself Yachiru due to having mastered all known sword styles, and was, and still is, considered to be the most diabolical criminal to have ever existed in all of Soul Society. The braid she usually has her hair in is to hide the scar of the only wound she has ever gained, inflicted by Zaraki, while the scar on Zaraki's eye was inflicted by her.
That being said, her motherly persona we've seen for the most part is implied to be as equally genuine as the Ax-CrazyBlood Knight side of her personality she's been hiding for centuries.
Also, Ichigo's mother Masaki was revealed to be this before meeting Isshin. Despite her bubbly and energetic appearance, she was very not happy with her current situation.
Dawn from Pokémon, oddly enough, fits this trope. She fails at keeping it a secret, though.
Not odd at all. She lost 2 Contests in a row - not even getting past the Appeals - before her self esteem broke. She seems to naturally have self esteem problems, maybe due to bullying as a child, and maybe her mother's wanting for her to be like her, and since she is a bubbly cutie who worries about her friends. Not at all odd.
This is actually foreshadowed from a very early point - pretty much her first episode - and hits its nadir with the 2nd lost Appeals Round, after which she tries hard to put on a happy face whilst not having the confidence to enter another Contest in a while. She finally overcomes the "Stepford" part when she wins the Wallace Cup (beating May, a more seasoned opponent). It was part of her Character Development - given how hard she tries to live up to her mother's legacy - and she comes full circle when she's happy with 2nd place in the Sinnoh Ribbon Cup.
Mary Magdalene in Chrono Crusade almost constantly smiles, even though she's constantly having visions of the future and the past, some of them horrifying and violent. In fact, she has so many visions she has no memory of her childhood or even her name—except for a reoccurring vision of Chrono killing her with tears streaming down his face. She's even smiling when she dies.
Mai Tokiha from Mai-HiME keeps a smile on her face almost constantly because she doesn't want to burden any of her friends with her personal problems, which include a dead mother and a sick younger brother.
The anime version of Shizuru: She manages to keep up a cool and semi-cheerful facade for the vast majority of the series, all while trying to content herself with being Natsuki's friend despite believing that she can't tell her how she feels. We don't see it break until Natsuki rejects her.
The over-enthusiasticprincess Amelia from Slayers, if one looks deeper, is a Type A; as a daughter of a prestigious and powerful royal family, she is subjected to horrific violence and carnage as her family battles over the line of succession to the throne. Her Missing Mom was murdered, in-series she sees one of her uncles and her cousin get killed attempting a coup, her sister has long since run away, and her father (the current heir apparent) is a go-to target for assassins. It's summed up well enough in the Light Novel she's introduced in:
"But you know," [Amelia] added, still sporting that strange smile, "I really don't like that you can't trust people in your own family around here." It could've been my (Lina's) imagination, but just then I sensed a great sadness in Amelia behind that bubbly facade. There was definitely more to that girl than met the eye.
Kyouko Mogami from Skip Beat!, due to having had an abusive, unpleasable mother, and later living and working in a ryokan (Japanese inn) where she picked the attitude of "clients shouldn't see you upset ever". Any time her real feelings and temper come to surface, she managed to put them back quickly, to not disturb the people around. Kyouko only breaks with this when she is properly informed that all her efforts will be not rewarded at all, and then realizes that living like she was constantly tending clients neither does her any good.
Complicating Kyoko's case is that after she discovers her "prince" Shou's heartless betrayal of her and snaps (in the first chapter), she continues from there. And the skills and habits she learned in her previous life and her tendency to live for others coexist really strangely with her new life goals. She wouldn't have made it so far if she wasn't the person her childhood made her, but she had to break with her childhood to go anywhere.
Really complicating her story? She has had a truly, deeply miserable, loveless life, but she always kept her spirits up. On the other hand, her Orphan's Plot Trinket was received ten years ago from a talented ten-year-old Hollywood Brat whose main sources of suffering were "I can't live up to my father's legend" and "My parents (who adore me) are busy a lot." A psychic exposed to the rock reports that the pain it absorbed from that kid was about a hundred times worse than what Kyoko's pitiful life has put into it. So apparently she really did keep her spirits up, and wasn't Stepford Smiling that much?
She was, but it turns out that kid's past includes guilt over maybe having killed someone so she wasnt overreacting.
There's also Takako Shimizu from Chobits, Shinbo and Hideki's Cram School teacher. She always smiles and helps them out, but hides how her husband ignores her in favor of his persocom...
Dita from Vandread was surrounded by people who were depressed often as a little girl. This, in turn, depressed her. She tried to cheer people up by acting as a ditzycutie, it worked, so the habit stuck.
In Sailor Moon Stars, Usagi/Moon slowly becomes one of these to hide her worry because Mamoru hasn't come in contact with her ever since he left to study in the USA. She thought he was working too hard in university, but unbeknownst to her, poor Mamoru was dead through Bus Crash.
In the live-action Pretty Guardian Sailor Moon, a somewhat similar theme's explored when Usagi learns from Mamoru that her own negative emotions are empowering Metaria and helping bring about The End of the World as We Know It, and so remakes herself into a Stepford Smiler. After Minako has died, Usagi tries to greet him with a teary-eyed, obviously fake smile, and when he tells her it's okay to cry now, she practically falls into his arms in tears.
Minako could have become one at the end of the Codename: Sailor V manga. In the final chapter she recovered the memories of the fall of Silver Millennium, discovered she's about to embark in a battle that may well end with her own death and bring The End of the World as We Know It, her one true love was revealed to be the Big Bad of the series and a subordinate of Kunzite before dying at her own hands, received a prediction she'd never find love due herself choosing duty over it, and renounced her dream of becoming an idol... And yet, as she returns to Tokyo she smiles cheerfully.
Seras Victoria from Hellsing. She's unnaturally cheerful and goofy for someone who's had all of her police partners killed, being nearly raped and killed by a vampire and then is actually turned into one. That's just the first volume/episode. Also her parents were killed in front of her and her mother was raped. In that order. The manga was a bit more subtle about her being a Stepford Smiler but the OVA series comes right out and says it.
Himawari Kunogi from Xxx HO Li C is a lovely schoolgirl best described as concentrated cute. She later reveals that she suffers a curse that makes her a magnet for tragedies, and everyone around her dies horrible deaths or at least suffers terrible accidents, ever since she was a little child. And she tells this story with a smile on her face.
Most of the members of the "Scratch" cult in Cowboy Bebop. Faye's smile while talking about getting rid of her debts by getting rid of her body is especially unsettling...
The girls from St Arsenal Academy in the manga Mission! School. At first they seem like your average happy schoolgirls. However, it turns out that they have been brainwashed and when they are provoked are revealed to be highly trained killers. The scary thing? They never stop smiling, even as they are taking on their enemies.
Misaki from Welcome to the NHK has elements of Type A and Type C. She appears to be an innocent, religious girl that wants to save Satou from being a hikikomori, but the truth is that she's searching for someone more worthless than she believes she is herself and help them to give herself a sense of purpose. Megumi also has elements of this, telling Sato she's successful and happy when she's actually gotten caught up in a pyramid scheme while desperately searching for a cure for her brother, also a hikikomori.
Anko from Bokurano spends some time as a Type A, after she's chosen as next pilot as punishment for hitting The Mole Youko, her dad is caught cheating on her mom, and Mrs. Tokosumi goes Lady Drunk mode out of despair. With the help of her friend Kanji, she gets better, just in time to fight and die in peace.
Mercedes Morcerf of Gankutsuou tries to maintain a perfect appearance and smile and loves to pretend that everything is okay even when everything really isn't.
Also Heloïse Villefort. She seems perfectly normal in her first few appearances, with a warm motherly appearance and pleasant smile. She is the stepmother of Valentine and is the second wife of the crown prosecutor Villefort. She is the biological mother of her young son Edward, from her first marriage. Valentine is to inherit all of the fortune, leaving her stepmother jealous because Edward doesn’t get a single penny. So when the Count seduces her and innocently introduces her to toxicology and gives her a deadly ring which releases a deadly poison Heloïse becomes murderous and tries to poison Valentine and her husband, as well as inadvertently almost poisoning Albert and poisoned one of the servants of the Villefort household. And she does all this while maintaining her angelic motherly facade up till near the end of the series when her husband finds out what she's been doing and points out that she's nothing more than a murderous insane woman. She tries to deny his accusations before she breaks down and collapses to the ground, finally giving in to her insanity. Her husband then puts her in an insane asylum for the rest of her life.
Corpse Party has the Type A Seiko, who smiles and strives to keep everyone cheerful despite being in a lot of pain following her mother's disappearance. The mask winds up breaking upon being accused of not taking anything seriously.
Kyouran Kazoku Nikki has at least 2. Kyouka, the self proclaimed God in Human Form, is actually a banished princess from a race of sentient creatures from a place called Shangri-la. In episode 26's Crowning Moment of Heartwarming of the entire series, she boldly proclaims that she is the child of Enka, and must be killed. She breaks down, claiming that she doesn't even know who she is since her people are effectively a race of sentient beings that possess you and give you animal ears, lending evidence to her being a type B.
Arguably Yuka is one as well, since, despite the fact that she smiles all the time, she was a "silent doll" for a large crime family, which means that everyone in the family abused her, both physically and psychologically, and it was her job to take it all with no reaction. One would think that this would make her a type C, but in actuality she is a type A who keeps smiling in order to not burdenher family.
Hayate of Magical Girl Lyrical Nanoha shows signs of being a Type A when in her Ill Girl phase, as Shamal notes that she hides her pain from those closest to them, and while she often comes off as cheerful, she confesses in the second Sound Stage for the season and the start of Episode 9 that she realizes that she might die soon, and for a long time, was not scared at all because of how lonely she was.
Shamal implies that Nanoha was this during while she was injured and when her recovering her ability to walk or fly was in doubt.
Izumi Maki constantly amuses herself by telling bad jokes and laughing at them alone Martian Successor Nadesico. While she appears initially as a Cloud Cuckoo Lander, she falls under this catagory as a Type-A, as the puns are designed as a coping mechanism to distract her from the pain of losing two seperate boyfriends.
Natsume's mother from Master of Martial Hearts spends all of her screen time as a Type A, because she used to be your average plucky Action Girl, until the took part to a Street Fighter expy for a MacGuffin supposedly able to grant wishes to the winner. However, she wasn't warned beforehand of the Fate Worse than Death awaiting the losers, so she was mindraped into helplessness, got her voice box removed and sold into sexual slavery. Upon escaping she found out that her younger sister, another Action Girl in tag team with her, was raped and beaten to death by the very man organizing the tournament... who also had married the winner (the indirect responsible for her tragedies) and sired a daughter as strong as her mom. She stays a smiling Cute Mute until the reveal, then is shown scratching a picture of her former self and her dead sister with nightmarish expression. Until worse happens...
Yuri Tokikago turns out to be one as well, likely a Type B due to her strong self-hate and hidden issues related to the (currently undisclosed) "secret" she has in her body. Also has Type C traits, considering the end of episode 14...
Like Misao, Tsubomi Hanasaki of HeartCatch Pretty Cure! was a Type A. Her parents were once major workaholics and, despite the loneliness, she had watched them go off with a smile. This went on for years and years until she finally broke down upon seeing a mother bird tending to its young. It was just pure luck that her parents had returned for notes they forgot in time to see their daughter break down and eventually changes job from botanical researchers into normal flower shop owners to make up for the lost time. The rest of the series shows her growing up from this incident and becoming a much stronger person.
Everyone in SoilNew Town but especially the missing Suzushiro family who remain cheerful in the face of vicious harassment and continuously deny that there's anything unusual about them to their daughter. For example they insist she has a birthmark on her back despite it being on her chest and they ignore the fact that her memories of her old town are off (EG "I lived on the third floor" - building has two floors - "school was behind the supermarket" - the only thing behind the supermarket is the edge of a cliff). It's heavily implied they're from another dimension.
As for everyone else: the housewives of Soil harass the Suzushiros after they get them into a pyramid scheme but the real instigator is the town president, an obsessive neat-freak pedophile dentist who raped all their sons (literally every boy aged 9-10 for at least the past 9 years), used the secret video cameras he put all over town to blackmail the housewives into harassing the Suzushiros, used a drill to torture one of his victims' mother into silence, and killed a bunch of cats to intimidate a homeless woman because her appearance violated his sense of "purity".
Mio Hio from D.N.Angel. Her initial personality of being a smiling Genki Girl is not her true personality. She's actually really depressed because she's actually a voodoo doll taken human form and she doesn't have much time left as a human being.
Rika Furude from Higurashi no Naku Koro ni (and Kai). She has been murdered and revived countless times throughout the series, and retains the memories of every death she has ever suffered; this has resulted in a mix of Types A and B - Rika is revealed to have lost pretty much all hope of saving herself from this brutal cycle, becoming very depressed and hollow inside as a result (she even gets drunk on occasion - this is a girl of about 10 years old - to drown out everything). Despite her struggles, Rika keeps a brave face, and constantly acts like the sweet, cute child that everyone expects her to be, to avoid freaking her friends out if anything (she does break this pretence at times to scare her killer(s), or to convince others to listen to her).
The series' main villain, Takano Miyo, also counts; she constantly acts like a friendly, helping hand to the arc's protagonist, sweeter than sugar, only to reveal herself as a cold Magnificent Bastard with one hell of a God Complex in the final arcs, who guns down anyone willing to mock her goals and beliefs.
How could we forget Rena? Underneath her cheerful facade, obsessed with all things that she believes are cute, lies a girl who is utterly broken over her parent's divorce, tried to kill herself, and lives every day with a smile just to make others believe she is happy.
Hino Kahoko of Kiniro No Corda following her Break the Cutie process tends to smile and act like everything is alright around her friends but if she's alone she tends to lose her smile and get depressed.
Koala from One Piece is a type A : During her time as a slave, she had to put on a smile at all times, because slaves who stopped smiling or cleaning would be killed. Needless to say, that smile hid. The poor little girl was so scarred by her time as a slave that she kept the Stepford Smiler façade even after she was freed. Fisher Tiger finally broke that façade by altering her slave mark to make it look like a sun, and telling her that it is OK to cry.
Chikane and Himeko both from Kannazuki no Miko. Himeko had a really terrible childhood and tries to hide her insecurities. Chikane is constantly trying to hide her feelings of love for Himeko...and eventually remembers that she killed her in a past life for a ritual to rebirth the world. Because of this, she was unable to help in the ritual to summon Orochi's nemesis so she wore the mask of the villain at this point in the series when she realized the reason why she couldn't help, because a deep part of her still hated the god. That was Himeko would become stronger and kill her to complete the ritual.
Mato Kuroi of Black★Rock Shooter is a major one. She hides her pain well and focuses all of her attention on fixing other people's problems rather than acknowledging her own, to the point that she starts denying she even has any issues.
Death Note: Misa. She acts happy and cheerful but Beneath the Mask she is psychologically traumatized, uncaring, self-destructive, manipulative and genuinely believes that criminals should die.
Miho often acts like this when she's feeling troubled. In Little Army, after her mother arrives, and her sister suddenly turns cold toward her and walks off, she smiles to her friends and insists that she's ok, but none of them believe her. In the main series manga, after hearing that she will be disowned if she loses against Pravda, she acts as though nothing happened the next day, and Yukari, who overheard what Miho had heard, makes note of this.
Anzu turns out to be one in light of the fact that she knows that the school will be shut down unless they win the tournament. Her facade only slips when discussing that.
Teru Miyanaga of Saki puts on a polite face for the press and public in general. Sumire chides her for this, saying that her "salesman smile is absolutely cruel", and while Teru insists that she's not completely lying, Sumire points out that sort of behavior is too different from Teru's actual personality.
Sanae Furukawa from CLANNAD maintains a cheerful exterior even after her daughter Nagisa dies giving birth to her granddaughter Ushio. When she finally cries five years later, it's truly heartbreaking.
Also from Death Note, Villain Protagonist Light, at Type C, with shades of Types A and B. He presents himself as positive, thoughtful, and cheerful to the world, but at the beginning of the series he's so bored and empty inside that a quest for a new world and godhood seems like a great idea; and of course, as the series goes on, that smile hides an increasingly unstable and cruel personality.
Mickey Simon from the Area 88 manga and OVA. He veils his war trauma, cynicism, and regret with a friendly exterior.
Okita "I smile constantly, love candy, play with the neighborhood kids, am pretty much a male House Wife to Hijikata, and am pretty much the most terrifying swordsman in all of Japan" Souji. Okita "I've been killing since I was eight and don't appear to actually regret it" Souji. That man's a TEXTBOOK Stepford Smiler!
This may be why his Gintama counterpart keeps trying to murder Hijikata.
The villainous Seta Sojirou, The Dragon of Rurouni Kenshin's best known story arc, also fits here — a cheerful young person who's capable of incredible violence because he has no soul or conscience behind the mask. (Or at least that's what he thinks.) He actually started doing this because it stopped his family from abusing him if he didn't appear bothered by it.
As for his reasons? Soujiro was constantly beaten as a child by his family due to being an illegitimate child, and learned to smile as a defense mechanism to get them to stop. He did this so much that he subconsciously repressed all his emotions, projecting nothing but a pleasant smile, even as he kills people. As a swordsman, this makes him virtually impossible to read and predict, and in addition to his speed and natural talent with the sword, this makes him a very dangerous opponent. This all changes when Soujiro battles Kenshin for the second time: Kenshin's worldview clashes with Soujiro's, irritating him to the point where his emotions finally return to the surface, causing him to break down in confusion. This state of emotional turmoil is what allows Kenshin to finally defeat him.
And again, Okita Souji, in the brief times he appears to interact with Kenshin and Saito Hajime. This is the popular portrayal of him in Japanese fiction in general, and it has been stated by one of his descendants that he did indeed smile frequently. (This is probably because Sojirou's character was based on Okita Souji.)
On that note, Kenshin himself. He hides the guilt and shame over his checkered past (and hides his temper) behind a cheerful and laid-back persona. Common for Walking the EarthRetired Badass types. The key difference is that the smile is not meant to be shallow; Kenshin really wants the smile to be real but keeps having to deal with his past, placing him somewhere between this trope and Becoming the Mask.
Add to that that apparently he served Aizen for a hundred years just to be in position to betray him at the last minute in order to avenge Aizen's wronging Matsumoto (he stole part of her soul) when they were children. She doesn't remember and moves on. He doesn't say anything and keeps his revenge. And he waited waaaay too long. So add a couple pounds of psychosis and Starscream to that description.
Hirako Shinji, too - he's hardly ever seen not smiling, and when he isn't it's because he's either really angry or something unsettling just happened. That man has been through a load of crap, and is probably in need of some counseling. Not as much as some other characters, but still...
Kisuke Urahara is probably one too, in a similar vein to Shinji. Sharing many of the same experiences, he carries himself with an enigmatic smile most of the time in public and can even act ridiculously goofy at times. Inside, he's really quite broken and when the smile fades he has many an introspective moment. Having to play The ChessmasterManipulative Bastard with everyone for 100 years - which means acting quite ruthless towards people he'd otherwise care about For The Greater Good - and distancing himself from all save his closest friends really doesn't help. It must especially sting because Kisuke was a Nice Guy before Aizen ruined his life.
You Takami from Deadman Wonderland seems to be one of the friendlier people in the prison/themepark, but he's not above stealing the antidote for Ganta's poison, taking someone's entire ear for their earring, selling out ditzy possible Dark Action Girl Shiro to the guards, and killing his own father, although the last part was because he thought he was protecting his sister. Then again he doubted that his dad could've really raped her so one wonders exactly what kind of person You was before being imprisoned.
Actually, his little sister, Minatsuki, killed their father. He even asks, upon her about to Back Stab him with her Branch Of Sin, if 'this is how you killed our father?'
After his confrontation with Minatsuki, he actually starts becoming happier/more content, and babies the hell out of his little sister, which is pretty strange considering that Minatsuki is an Ax-Crazy, Psycho for Hire, Combat PragmatistBlood Knight who is a very experienced killer and has been a Combat Sadomasochist for the last 5 to 10 years. However, this change seems to coincide with the fact that Minatsuki mellows out from outright sociopathic killer to just Sociopathic Heroine because of her interactions with Ganta and You. That said... if you threaten Minatsuki, You will probably try to beat you up, but if you piss Minatsuki off, she will probably tear your head off. Literally. Nuff said.
It's been implied at this point that Takuto Tsunashi of Star Driver, up to this point a typical kind, cheerful, BadassIdiot Hero with a bit of Cloud Cuckoo Lander mixed in, at the very least has some Hidden Depths that are... well, not nice, at the very least (and at the most, this is all a facade and he's completely SCREWED UP) if these implications are to be believed. Knowing Yoji Enokido, these are probably going to be fully explored by the time the series is over.
In fact, Johan's own ability to project a happy, kind, innocent and childlike demeanor worthy of a cherub, other than for purposes of manipulation and as a cover for his true sociopathic nature, doubles as a mask for covering up his dark past, spent in the orphanages of the Communist bloc.
Also, Johan's muscle and pawn, Roberto, harbors an extremely creepy Stepford Smile, as seen here◊. Let's just say that it's a common trait amongst Kinderheim alumni...
Even before the series hit rough territory in the Acid Tokyo arc, in Outo Country Kurogane had blatantly told Fay he knew he was hiding something. During the Celes arc we find out just what he had been hiding. We learn about his past and that his real name isn't Fay, but Yuui; Fay was the name of his identical twin who sacrificed himself to let Yuui live... but Yuui thought he killed his brother. That's not all, either. Fay has other dark secrets we learn about. No wonder he tried to hide behind a smile.
Chichiri from Fushigi Yuugi has a literal mask that helps him pull off the goofy, care-free smile; it's a significant plot-point when he takes it off to relay his tragic backstory.
Yuki Sohma from Fruits Basket is so terrified of being rejected by his peers that he uses his numerous skills (martial arts, good looks, charisma, etc.) to hide the inferiority complex that Parental Abandonment and Akito's Mind Rape gave him.
Souichirou Arima from Kare Kano is, at the beginning, as much of a Stepford Smiler as his girlfriend Yukino is. Except that while Yukino does it out of obsession with her own image and is a bit of a Butt Monkey for that, Arima does it to prove himself a worthy person after hearing his relatives wonder if his parents' bad traits may be passed on to him even after they left him to be adopted by his uncle and aunt after years of neglect, and also because of the abuse doled on him by his birth mother.
Trigun's Vash the Stampede combines this with Obfuscating Stupidity to create Crouching Moron, Hidden Badass so that nobody realizes just how dangerous he is, or what horrific memories and experiences he lives with every day. In the whole anime series, only Nicholas D. Wolfwood is able to see right through Vash's act - in his first episode, Nicholas shares some food with a pair of hungry children while Vash watches, then tells Vash that he looks good with a real smile on his face, not the fake one he's been showing.
Wolfwood has the advantage of inside information. The old Professor among the Last Unfallen humans, who's known him for decades, can also read through this kind of thing, although Vash doesn't try it so much with him. Stuff like bickering childishly with Wolfwood apparently reads as 'real' to both these parties.
Manga!Millie, who's dumbfounded by this, eventually compares Vash's fake smile with the grey colour you obtain when you mix paints of all colours.
That's in Maximum #39 'Colorless Emotions,' the first time Vash reflexively uses the angel arm to block a bullet in a relatively casual gunfight. (Read: the people trying to kill him aren't plot-related characters.) Meryl cracks up briefly at seeing it after the trauma she had last time he used it, and the townspeople conclude he's a demon and start ''stoning'' him. Wolfwood snarls at them. Crowning Moment Of Heartbreaking:
Millie: Vash! I don't understand. What's happening? What's wrong? When it's as hard as this...you can still keep smiling like that?!
Vash: [Beat panel, still smiling.] What other expression should I make? I don't know anymore.
Nicholas D. Wolfwood himself thrives on this trope, although it's clear almost from the beginning he is a dark, conflicted, and potentially angsty character.
And let's not forget that in the manga, young Knives managed to hide his feelings of agony and murderous hatred from Vash and Rem by having fun with them just as usual, making crepes while smiling and laughing, claiming to go all 'business as usual' because he had to go on with his life etc.
Cho Hakkai from Saiyuki qualifies, as he smiles constantly even while fighting, despite his angsty past which includes but is not limited to killing over 1000 demons to rescue his lover Kanan (who is really his twin sister), then watching Kanan kill herself with his sword because she was raped and impregnated by a demon, then to top it off, becoming a demon himself. Whew. His companions note that whenever he actually does stop smiling and looks angry, it's extremely scary.
Manages to overlap with Slasher Smile without changing his expression. Creeeeepy.
Shuusuke Fuji of The Prince of Tennis was a bit like this due to the problems with his younger brother Yuuta that caused him to bear a huge guilt. He starts acting more genuinely cheerful when he and Yuuta patch their relationship.
In Tokyo Mew Mew, Masaya Aoyama is revealed to be one of these, keeping up his "perfect" mask to hide the fact that he hates all of humanity. Ironically, most of the fandom seems to ignore this, taking his Smiler-ness as both his true personality and an excuse to pair Ichigo up with someone else.
Quiche also seems to be a Stepford Smiler, butisaType C . He keeps his cheerful personality perfectly, for a quarter of the series. Then he goes through a few breakdowns and rejections completely loses it in episodes 45 and 48.
Prussia in the Christmas strips is "So happy being alone". Really.
Lithuania's a minor case. He can show fear and frustration from time to time, and he's genuinely a really nice guy. But he'll often be smiling and laughing while Russia is stalking and abusing him, or when the girl he loves is breaking his fingers, or when his boss is overworking him, or when Poland is giving him severe stomachaches...he also has No Sense of Humor.
APH Dark Fic often interpret characters as fitting this trope, especially the most loudly cheerful and dense ones like America, Italy, and South Korea, considering that just about every single nation has had their fair share of brutal historical events in real-life.
Since APH is based on world history, (with one of its initial lead characters being freaking Nazi Germany), all its characters are all prone to act like sociopaths from time to time, because the community of nations has never, ever been civilized or characterized by good faith.
Considering the Lighter and Softer tone of the manga, however, this is greatly overblown by fanon, which in its tries to accommodate canon to more Real Life-like history ends up more often than not making the characters fall victim to lots of OOC behavior rather than finding a medium.
In all fanfictions with darker themes with Italy as a character, he will be a Type A. Guaranteed. No exceptions.
In America's case, he does play it straight when around Russia, responding to Russia's behavior by acting similarly; America keeps his goofy smile even when showing aggression towards him (unfortunately, fanworks tend to overlook this, often having these two scowl, smirk, or genuinely smile at each other instead). It's possible he may act like this to all his enemies.
Tohma Seguchi of Gravitation initially seems to be a polite, mild-mannered man until he shows other characters just how far he's willing to go to protect his brother-in-law Eiri, which includes pushing a man in front of a car and making Eiri break up with Shuichi by threatening to hurt Shuichi if he didn't do so. All while smiling calmly. He stops smiling for more than one panel only when he's in full-on Yandere mode.
In the manga sequel, Tohma seems to have shifted from a mostly Type B to a Type C. He holds an axe over a comatose Shuichi, threatening to kill him if he doesn't wake up. He does this while still maintaining a huge smile. He's completely type C in the 10th volume when he comes face to face with Yoshiki Kitazawa.
Tohma's younger cousin, Suguru Fujisaki, is also a Stepford Smiler early on. At least until Shuichi's lazy work schedule gets to him and Suguru ends up panicking about how the band will ever finish its next album instead of worrying about maintaining a smiling appearance. He still has moments where he forces a smile, like when Tohma confronts Suguru in his office about who will be paying for the destruction of NG.
Kaito Kuroba/Kaitou KID from Magic Kaito thrives on his use of "Poker Face", an important skill taught to him by his father when he was young. Kaito's poker face (both as Kaito and KID) is pretty much always some variation of a smirk, and he rarely lets it drop even when things go wrong. Let's put it this way: if Kaitou KID ever stops smiling, everything has Gone Horribly Wrong.
Break is also one. Then again, having the family that you tried to save end up dying even at the cost of losing your eye is enough to shock someone into faking smiles forever. A combination of type A and B, he never lets the smile fall except when he's close to his breaking point. Like many of the characters in this series, his smiles seem to become more and more genuine as the story progresses.
Jack is a combination of all three types but especially Types B and C. He is described by many characters as appearing "empty" inside even before Lacie's death, at which point he becomes Type A and then, increasingly, Type C. Needless to say, he's quite the complex character in a series known for complex characters.
Levi, one of the past Glens, qualifies for all three types. It's pretty hard to keep smiling like that when you're rotting alive painfully and one of the people you cared about ended up being dragged to the Abyss to be Deader than Dead, but somehow, he managed. His "friendly advice" to Jack reveals him to be something of a Type C as well.
Leo has become this way as well after Elliot's death. He's equal parts B and C, having essentially Stopped Caring, and Oz even comments, "You don't want to destroy anything. You're just trying to destroy yourself."
Oh so many people in Code Geass. Lelouch Lamperouge and Suzaku Kururugi, to start. Lelouch is a Type B (seems kind and cheery, but is hollow and futile inside), at least initially, and Suzaku becomes a Type A (seems kind and cheery, but feels sad and depressed) over the course of the series.
And Rolo Lamperouge. He seems like a perfectly normal and very nice kid ... until people start dropping dead around him. Not to mention he can be considered Type C due to his Cute and Psycho and Yandere tendencies.
Magi's Jamil is a good example. He's all smiles on the outside, but quickly reveals himself to be a sword-happy Type C
Naruto himself. He smiles near-constantly, which, during his childhood, was to mask the sadness of his lonely life. Those who are closest to him are able to recognize when his smile isn't genuine (which is, surprising enough considering his personality, much of the time). He will tend to mask his pain with a smile, such as when he promises Sakura to bring back Sasuke for her before and after the retrieval mission. He even admitted to Hinata that the smile is a mask, and Pain put him on the ropes by breaking him down with words, getting him to second guess his own actions. Before the Chunin exams finals, he admitted that he viewed himself as a loser and tried to act cool and brash to cope with this.
Make no mistake that Naruto is an optimistic, lively person by nature, but given how litle reason he had to smile in his childhood, it's small wonder not all of it's totally genuine. If he didn't have the zest for life which he generally displays, everything Naruto had to deal with would have probably driven him mad. As he slowly gains recognition and respect, the smiles appear less but in turn become more genuine.
From the same series, Sai. As part of his indoctrination into Danzo's forces, all of his emotions were stripped away until he was emotionally empty. When assigned to Naruto's team he tried to teach himself how to smile in order to pass himself off as normal, but Naruto easily saw through it. He still has trouble understanding and feeling emotions, but he's getting better... He will never be normal, but who wants normal?
Iruka was a mild example during his childhood (after his parents' deaths).
Mizuki shows signs of being a type C, especially in his Monster of the Week arc. Even as a child he was shown to have virtually zero empathy for Iruka's suffering.
More specifically, he tells Iruka that he acted supportive, hoping the positive attention Iruka recieved would rub off on him. His girlfriend believes he was once genuinely kind-hearted, before the Envy he had slowly made him cruel until the good was gone (it probably didn't help that suspicions on him killing a teammate on a mission led to him being distrusted and denied a promotion, which made him more resentful). Whichever is true, his kind smiles are certainly a lie in the present.
Itachi's gentle and loving, if somewhat distant, attitude in Sasuke's flashbacks before the massacre count as Type C. Can probably be considered Type A once we learn the truth about him.
Jiraiya puts himself down a lot despite acting goofily perverted and smiling a lot. Even in his last moments he believes that his life was a complete waste and that he was a loser. His only goal in life was to have an awesome death. He managed it.
Kakashi too, who smiles when he tells Sasuke everyone he loves has already been killed, and generally acts rather carefree, but is actually filled with self-loathing and feelings of guilt over his teammates' deaths.
Dragon Ball Z: Future Trunks. In his first appearance, he's friendly to the Z Warriors and is polite to a fault with them. However, he comes from a horrible future where every main character is dead. Made worse because his father Vegeta apparently ignored him, though at the end he leaves at peace.
Bulma: Hey, I'm just gonna throw this out there, but you're really cute. Trunks: Well, my mother always said I was a cute kid... Bulma: Oh, a momma's boy, huh? I'll beyourmommy. Trunks: (internally) AAAAAAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!
Part of the Dragon Ball Z fandom sees Gohan as this, post-Cell Saga. Considering what the poor guy wentthrough, it's not hard to understand why.
Monkey D. Luffy is thought of this by a good portion of the One Piece fandom because of his relentlessoptimism considering all of the terrible things that have happened to him in the past. But the main reading is still that he's just that stupid.
A recent case has the three princes of the Ryuugu kingdom (Fukaboshi, Ryuuboshi, and Mamboshi). The three are seen smiling and, in the last two's s case, singing and dancing in a last attempt to keep their little sister Shirahoshi calm... after all four of them just witnessed their mother Otohime being shot and dying.
Also thought to be this are the Boa sisters and some of the other slaves of the Celestial Dragons.
Brook is definately one of these when we first meet him. Prior to encountering the Straw Hats, he's been trapped on his broken-rudder ship, drifting around the foggy seas for 50 years after he and his crew died. And five years ago he lost his shadow to Gecko Moria, meaning he can no longer go into the sunlight without disintergrating. And it's implied in flashbacks that the isloation did something to his head. Now he acts like an Upper-Class Twit with poor manners. As he energetically summerizes his existence, Sanji asks, "Why the hell are you so cheerful? Your life sucks!"
Game X Rush has smiling, laughing, charming Yuuki, who's hiding a treasure-trove of Capital-I-Issues in his head. Memori reflects that "Even a face laced with a tiny bit of pain... is a thousand times better than seeing that mask." It's implied that a large part of Yuuki's impetuous to stay around Memori is that Memori can discern the real smiles from Yuki just being a Sad Clown.
The titular Hayate the Combat Butler. Recent chapters/episodes have implied that his kindness and decency are coping mechanisms he developed to cope with the harsh, nay, downright vicious realities of his life rather than his fundamental personality.
Certain chapters and episodes of Seitokai no Ichizon imply that Ken's happy-go-lucky persona is a defence mechanism to keep him from a severe emotional trauma from back in junior high, and not his actual personality.
Durarara!!: Kida is not naturally that cheerful — it's a front he puts up for Mikado's sake.
Yuki Giou of Uragiri wa Boku no Namae wo Shitteiru clearly has some issues of self-worth stemming from being abandoned by his parents when he was real young. However, if someone should ask him if he's doing alright he usually gives them a cheerful smile and says "nothing's wrong" but tends to get depressed if he's by himself.
Okami in Code:Breaker initially seems to be successfully pulling Obfuscating Stupidity on his class with his Nice Guy persona. However, one chapter has several classmates wanting to cheer him up, commenting that he seems to be very sad but putting on a happy front for their benefit.
The lead... no, all of the Code: Breakers, seeing as they're super-powered Ax Crazies put to good use by the government (or something).
Tamaki Suoh from Ouran High School Host Club is this. He has to live with the knowledge that he'll never be the heir to the Suoh dynasty, that his grandmother despises him simply because of birth circumstances (his father married a lower-status French woman instead of the arranged girl) and that he may never amount to anything famous. Until the last two episodes of the anime, he covers it up remarkably well, mostly by holding ostentatious events with the host club. We also hear about it during Kyouya's backstory, when he explains how he and Tamaki became friends and started the host club.
Kumagawa Misogi of Medaka Box manages to oscillate between all three types somehow. From his first appearance it is obvious, that his smiling and cheerful appearance not so much hides his evil and insanity, as is cultivated to disturb his opponents even more (type C). Kumagawa's former doctor believed that he really had no emotions at all (type B), until at one point he got actually enraged to the point of losing control (again folding to type C). And it is quite believable (not thanks to his Motive Rant, as he's a compulsive liar, but thanks to the track record of this manga so far and his later Heel-Face Turn), that he is also an extremely embittered and twisted example of type A.
This applies to all Minuses in Medaka Box. As Kumagawa put it:
Even if things don’t go the way you want them to. Even if you lose. Even if you don’t win. Even if you look like an idiot. Even if you’re walked on. Even if you’re kicked. Even if you’re sad. Even if you’re bitter. Even if you’re tired of it all. Even if it hurts. Even if it’s hard. Even if you’re weak. Even if you aren’t right. Even if you’re humble. Through all of that, we Minus always laugh.
He's also a deconstruction of shonen heroes, and possible a rare type of psychopath with fascinatingly Player Centered Morality (i.e. "This serial killer helped us learn a lot by fighting us, so I'll show him mercy in good, shonen-hero style, even when you point out that he will go kill more young women and eat them if set free. Because he helped us.") It puts the manga-trained reader into the weirdest headspace after a while.
Well his best friend Killua has killed possibly hundreds of people in the past. Gon himself, in the life of a Hunter, will probably have to kill someone at some point. Its hard to condemn someone for killing when doing so will make you a hypocrite.
During the Ant Arc he kind of snaps. No past-pain comes into it, though. Just his failure that got someone important to him killed and his determination to be revenged.
And Hisoka is a rather crazy Monster Clown and frequently wears a smile on his face.
Ryou Bakura of Yu-Gi-Oh! is one of these. When he first appeared in the manga, the Millennium Ring was giving him chest pains, but he covered it up so people wouldn't find him strange. He overall acts incredibly cheerful most of the time, but he also hides his problems, which is pretty bad for the protagonists. Yami Bakura, however, takes advantage of this, as he often pretends to be the normal Bakura so he can carry out his evil plans on the quiet, meaning he does this on purpose.
He ambiguously stops existing at some point in the third season for no particular reason. His friends apparently do not care. Or notice. Or something. He kept turning into the crazy guy so they couldn't trust him, and the pharaoh decided killing him was acceptable given the threat to the world, so maybe he committed soul suicide. Or just retired to his soul room forever.
Duo Maxwell from Mobile Suit Gundam Wing is a Type A who seems to be upbeat (and snarky), but really is traumatized by the war and losing many people who were close to him.
Duo is the most cynical pilot by some way, and also the only one who doesn't seem to have something childlike about him, although he's the one who seems the most childish on first meeting. He hasn't been sheltered, trained, or broken, just hurt and rolled with the punches; he's almost certainly the most stable of the five of them. Cynics are hard to surprise, after all. So...questionable, despite Duo Torture being a major hobby of the fandom.
Despite being weird, the English dub that made him sound forty wasn't the worst casting choice ever.
Kei Yuzuki from the second Vampire Princess Miyu OAV is a good Type B. He hides his boredom with life in general, his feelings of inferiority towards his more academically-successful siblings and his apathy towards his Education Mama's constant pressure under a polite, soft-spoken, beautiful princely mask.
Also Lemures from the third OAV, who appears to be a helpful Dandy in his human form, but is soon revealed to be a scary Type C and a Yanderefor his old friend Larva, whom he has kidnapped and imprisoned in hopes to free him from Miyu.
Lavi. Or perhaps in this case we should say Bookman Junior, since "Lavi" is just another one of his aliases. (He started changing once he started to get into his new role more and came close to his teammates though.) But what was the actual person like before joining the Order? During the fight with Road, Lavi gets flashbacks- what we see is a jaded and cynical young man who has lost all the faith in humanity, who doesn't give a damn about anything. He socializes with people only because it helps him to get information more easily ("Let's be frivolous and friendly like always"), face all smiles, not being a bit like keet we know he is in the series. It's even mentioned in Reverse Novel 2 how his eyes seemed dead when he first came to Black Order.
But when you consider his past, is it any wonder he turned out like that? After all, growing up while recording wars and seeing bloodshed wherever you go isn't exactly the happiest childhood there is. To sum it up: Bookman Junior is Stepford Smiler Type B, perhaps a bit milder version since he's not totally soulless, maybe a bit hollow, yes, but not empty. After becoming Lavi, his fake smiles have started slowly turn into genuine ones.
"1 year...2 years...The time within the order passed on. I soon came to the point where I didn't know whether my smiling face was a lie or not."
Some interpretations of Allen's character. Allen tends to smile and throw out optimistic and enthusiastic support at the drop of a hat when around his friends, but whenever he's alone he tends to be either beating himself up, wallowing in some deserved self-pity, or worrying about his entire freaking existence.
Narusawa of Jazz is a Type B, having absolutely no life outside of being a doctor as that was all his parents cared about. The only thing he seems be passionate about is jazz music and only mildly so.
In Akuma to Love Song, Yuusuke epitomizes type A, and even calls it "Lovely Transformation."
Amasawa of The Weatherman Is My Lover is a Type A, as in spite of his outgoing and eccentric personality he secretly never got over the guilt of his parents' deaths and lives a really isolated existence as a result.
Mikael from Tenshi Ni Narumon is a weird mix of Type A and C. He usually tries to act all calm, cool and composed - like in the first 13 episodes of the series - smiling gently when talking to Noelle and being all nice and polite when dealing with her family. But when his teacher, Raphael showed up, it turned out that Mikael, when indoors, is just a very serious, uptight and insecure boy. And then he went all insane and evil when things didn't go as he planned and ended up just pathetically broken. Fortunately, he got better and returned to his uptight and highly anxious self.
Tetsudo "Poppo" Hisakawa from Ano Hana is a type A version. He's a happy, cheerful guy who loves to travel the world, but that is to cover up the guilt over his inability to save Menma from drowning over 10 years prior to the main story.
Soubi of Loveless is a pretty extreme type b. He seems happy and cheerful, but is actually an Extreme Doormat whose been essentially conditioned into only existing to obey his master. Given his background, he could arguably count as a type a, as well.
Kotetsu from Tiger & Bunny is implied to hide feelings of worthlessness and unhappiness with his life under his Hot-Blooded demeanor. Word of God supports this, stating that Kotetsu exaggerates his behavior as a means of putting people off of him (because he doesn't think he's worth worrying over), that he's never fully sorted out the emotional baggage anti-NEXT discrimination's saddled him with, and that he was on the verge of major depression at the beginning of the series.
Kaworu Nagisa of Neon Genesis Evangelion seems to fit this trope as well. He's always smiling, but in reality, he just wants the world's end. It Got Better for a while, but shortly after, it all goes to hell.
Also, Ryouji Kaji, who was smiling calmly in the very moment he was shot to death
Shinji: For most of the series he walks around quietly with a little smile on his face, even when it becomes clear he's dying inside.
Muruta Azrael of Mobile Suit Gundam SEED. While his evil is public knowledge, his enthusiastic personality and dark sense of humour are a ruse to cover just how unstable he is. When he finally slips up in the penultimate episode, the results are nothing short of horrific.
Koizumi Itsuki from Haruhi Suzumiya always keeps a constant smile and a cheerful attitude, regardless of how much is Haruhi casting upon the Universe. Granted, he's still mostly sane and calm, but his Stepfordness always creeps Kyon out to no end. But when his smile disappears... you better start fearing the worst! He actually expresses an open jealousy towards Mikuru and all the other members of the SOS brigade, because he has to keep a facade of his true personality to fit Haruhi's expectations of his, while the rest do not (aside of Mikuru's Obfuscating Stupidity). Worse yet, he's so good at his Stepford Smiling that it's hard to tell if he's type A, B or C.
At points in the novel it's made pretty clear that Itsuki's finding it difficult to keep smiling, such as in volume 9 he's been unable to sleep well for a lengthy period of time due to constant closed space activity, appearing exhausted and using a rather forced version of the usual grin, which falls off if he isn't concentrating. What is he really thinking? Who knows, it's the one thing he doesn't really talk about. Probably.
To add fire to the fuel, in the eleventh novel, he cheerfully prepares to fight (and probably kill, it wasn't made clear afterwards) the novel's Big Bad. Note the word cheerfully.
Shou Tucker appears to be a kind, gentle man, but in reality is insane enough to transmute his daughter and his pet dog into a chimera.
Selim Bradley from the manga and Brotherhood anime is a sweet little boy. He's actually Pride, the eldest, and arguably most sociopathic, of the homunculi.
The Dwarf in the Flask - later known as Father - needed to be this to fool Slave #23 - later known Van Hohenheim - into going along with his plans.
King Bradley is this in the original 2003 anime; he appears to be a kindly family man but is actually the homunculus Pride.
Griffith of Berserk is an excellent commander, a masterful swordsman, graceful, elegant, and charismatic. He's also got serious problems, mostly involving his greatest warrior Guts. When Guts leaves the Hawks, it starts a downward spiral for Griffith that would culminate in the betrayal of all the Hawks in order to become Femto during the Eclipse as well as his monstrous rape of Casca.
Not to mention that this trope is played eerily straight after the eclipse and Griffith reincarnates himself into the real world with a brand new human body. Lacking empathy and just emotions in general, the most that Griffith ever gives to display any form of emotion is a soft smile which only serves to give the effect that he's constantly giving you the Kubrick Stare. It's amplified with his unsettlingeyes.
In Blue Exorcist, we have Yukio. Smiling, nice, accomplished and smart...recently has been slipping and showing his insecurity, jealously, and hints of a far from stable mind set. On top of that, his own brother Rin, who is cheerful, book dumb, and loyal to a fault, has been showing signs that notalliswellinhisworld. The latter is worse than the former; while Yukio is pretty good at hiding his issues, Rin outstrips him by far, being capable of smiling and pretending things will be alright even when they definitely won't be and he's internally wondering why he is still alive. See the Impure King arc for that prolonged incident of fake smiling.
Mixed Gender Examples
Outside of the ones that act fairly emotionless, many Contractors are like this in Darker than Black. November 11 and Amber are a good illustration, as their cheerfulness seems to be inversely proportional to their sincerity.
Krista Lenz is the sweetest, kindest girl anyone has ever met and referred to as the "Goddess" of the 104th as a result. She's actually deeply troubled, with a dangerous martyr complex and a need to be seen as virtuous and kind regardless of the risk it places her or others in. She's getting better.
Reiner Braun is a surrogate big brother to the others, always trying to offer reassurances or awkward jokes even in the worst situations. He's actually a Type 3, being driven slowlyinsane with guilt over his crimes as The Mole.