Sanity Slippage / Anime & Manga

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• Aramaki from 7 Seeds behaves a little stiffly and strangely when he first appears. Justified since he had spent the last 15 years with no company except his dogs. He gets better once he starts hanging out with Hana.
• In Attack on Titan, several characters experience varying levels of it due to the very nature of the world. Anyone that hasn't had a Freak Out, slowly gone mad, suffered a Heroic BSoD, or otherwise shown signs of coming apart at the seams probably died before they had a chance to crack. The trauma the survivors experience is a major theme, and teetering dangerously close to the edge is not only common, but completely understandable when the risk of being Eaten Alive or watching your friends suffer the same fate is an everyday thing.
  • Bertholdt seems to become more and more hysterical after The Reveal. Reiner is just as bad if not worse after that same reveal. The fact that Reiner's been teetering on the edge of complete insanity for a long time is particularly shocking, with his Villainous BSoD continuing to get progressively worse.
  • In a side story, an Aberrant Titan is shown to be experiencing one. It goes from calm, to whimpering, and finally begins to cry while clawing at its own face until it nearly tears its own eyes out. Then it goes back to normal behavior, and eats the unfortunate soldier it had caught.
• Black Clover: Langris goes through this in the Royal Knights Selection Exam when Finral tries to fight him, which causes him to remember how others preferred Finral for his kinder nature, conflicting with his parents' belief that he's superior. This, coupled with the fact that Finral is fighting without using lethal force like Langris, which leaves him feeling as if he's being looked down upon, only serves to irate him even more. Langris's reasoning that he has to beat Finral at everything causes him to try to kill an already severely injured Finral, only stopping when the entirety of the Black Bulls stands ready to tear him a new one if he tries.
• Liang Qi, not the biggest bastion of sanity to begin with in the Canaan series, rapidly starts slipping after Alphard, who she has an obsessive devotion for, abandons her, resulting in a Villainous Breakdown that ultimately leads to her having to be given a Mercy Kill after she gives herself a dose of the Ua virus in a mad bid for Alphard's attention, only to learn very painfully that she doesn't have the genes for synaesthesia.
• Happens quite a few times in Code Geass, with results ranging from a Heroic BSoD to Insane Laugh... to attempted hallucinogenics use. And attempted murder-suicide, on a couple occasions.
  • Not to mention the final arcs of each season, though the second one is more ambiguous, depending on your opinion of Lelouch Lamperouge's logic (hint: either bringing the world to it's knees and united in mutual suffering then assassinating yourself is a good plan, or Lelouch is mentally unbalanced. Or both.), the first is clearly a plan to force someone to shoot you, then blaming them for it, with no obvious measures to limit the likelihood of dying. Not to mention Lelouch's attempt to trap himself and his father in a giant chamber, devoid of food, dooming them both to starvation, if not for the insufficient explosives.
  • One particularly notable incident is when Nina goes full on Yandere, to the point of showing up with a nuke to kill Zero, even though it would likely take everyone around with it, even her friends. She sounded beyond unhinged at the time, wild-eyed and shouting with grief and anger. Thankfully, it was defective...but then Nina switched to working on Applied Phlebotinum fantastic nukes. Oy.
• Happens to Jeremy in A Cruel God Reigns. He could also have some possible Madness Mantra, at one point repeating "Hallelujah" over and over again while Greg ties him up between his bed posts in a very crucifix-type manner and whips/rapes him. Jeremy also laughs at the news of Greg's death (which he caused), tries to seduce his uncle, and plays mind games with Ian and generally seems unhinged the further the story goes.
• A strong theme of Cyberpunk: Edgerunners is demonstrating what kind of horrific effects cyberpsychosis has on the human mind:
  • The heavily chromed Maine's violently erratic behaviour plays a sizeable part in turning the Tanaka kidnapping into a profound clusterfuck.
  • David's natural resistance that allows him to get considerable cyberware without mental degradation is shown to have its own limits. He starts to experience truly disturbing hallucinations by episode 8 (not helped by a good helping of PTSD and guilt) and his ultimate merging with the cyberskeleton sends him down a road of trippy madness by the finale that powerful immunosuppressants can only barely stave off.
• Light Yagami from Death Note. He gets crazier with every passing episode barring the time he loses memory of the Death Note.
• Dragon Ball
  • In Dragon Ball Z, the more Frieza taps into his true power, the less sane he becomes, likely because he can't accept how a bunch of lesser beings refuse to die and force him to actually fight them seriously. By the end of his fight with Goku, he is closed to foaming at the mouth and keeps attacking Goku even after he loses more than half of his body. His sanity actually becomes worse in Resurrection 'F' and deceases more throughout the movie. One minute he is acting like his usual calm, polite self, the next he's screaming and snarling. His time in Hell clearly didn't do any favors for his sanity, even if he tries to hide it at first.
  • After becoming Super Perfect, Cell is noticeably more unhinged than he already was. His Psychotic Smirk is now replaced with a permanent Slasher Smile, he constantly shouts his lines, makes weird facial tics, and goes on bizzare tangents about how perfect he is.
  • When Goku went Super Saiyan the first time, he is notably not completely sane. He is nearly consumed by hatred and rage that he puts defeating and humiliating Frieza above escaping an exploding planet. His shifts from his normal Tranquil Fury self to him screaming in anger also shows how unhinged he is. Goku's fully aware of his deteriorating mental state during this time, and specifically warns Gohan to get away from him before he completely loses his mind.
  • When he ascends to Super Saiyan 2, Gohan's sanity takes a major hit. He prioritizes tormenting and humiliating Cell for his crimes over actually killing him, even deliberately letting him regenerate at one point because he felt Cell deserved to suffer as much as possible, and not even Goku, his own father, can reason with him. He only comes back to his senses when Goku is killed because of his actions.
  • In Dragon Ball Super, Zamasu and Goku Black were none too sane to begin with, but their eyes become progressively crazier and crazier the longer the arc goes on. And when they become Fused and later Infinite Zamasu, all that's left is a mindless Eldritch Abomination hellbent on destroying everything he sees.
  • Jiren of Universe 11 starts to suffer from this the more Goku keeps getting back up and attacking him, but he really loses it when Ultra Instinct Goku kicks his ass and tears all of his beliefs about strength to shreds. This leads to his attacking the spectators, where not only Goku's friends were sitting, but the rest of the Pride Troopers.
• An entire episode of Elfen Lied is dedicated to the Ax-Crazy protagonist Lucy's childhood, in which we get to see just how she got so unstable and murderous through this trope.
• Full Dive has Alicia steadily lose her sanity within the first episode. First, she's starts out as a kind, sweet girl who is also Hiro's childhood friend in the game. Then, she sees her brother Martin dead on the floor, bleeding out with a knife in his throat after Hiro tackled him. Then, she grows angrier as Hiro constantly tries to apologize and panicking, not giving her a clear answer on what he's going to do. Finally, when he runs out the door upon listing to her Madness Mantra, Alicia had reached the Rage Breaking Point and proceeds to chase him down like a rabid dog, showing she has gone murderously insane.
• Fullmetal Alchemist (2003): Scar's older brother is revealed to have suffered this. The combination of his lover's death, failing to revive her through human transmutation, losing his genitals in said transmutation, and the imposing threat of a war on his home eventually pushed him over the edge. Using his own body, he planned to create a Philosopher's Stone out of Ishval's people during the massacre. He wandered out onto the battlefield completely naked with Ax-Crazy eyes and tears streaming down his face as Scar watched in horror. It didn't end well.
• Future Diary: Quite a few characters have already slipped by the time the story starts, but we get to see the entirety of Yukiteru's eventual descent.
• In Gankutsuou, we get this when the Count of Monte Cristo watches Albert whom he had grown very fond of, leave his ship to witness the start of the Count's revenge on Albert's father. At first he sobs desperately and then he breaks out into hysterical laughter. And from then on, he's out there, madly pursuing his revenge. Andrea Cavalcanti also does this, going from creepy to outright deranged by the end of the series. And let's not forget Danglar's Death by Materialism, preceded by a good amount of madness...oh, and Fernand Mondego, who snaps to the point of shooting his wife and son. Or Héloise de Villefort. Yeah, this show is pretty much filled with the trope.
• Gintama: Yamazaki gradually loses his mind as a result of having survive on nothing but milk and anpan over the course of a month-long stakeout. First, he starts sparking anpan into the faces of random people, then starts seeing and hearing nothing but anpan, then finally snaps, with one of his log entries consisting of nothing but "ANPANANPANANPANANPAN". He never completely recovered from the incident, with him having random relapses in his insane behavior from time to time.
• In Gregory Horror Show, the Hell Hotel can only be found by people who have already begun to slip a little (the first guest may have been going mad with boredom from his monotonous life, and the second guest starts to slip when her best friend marries her ex-boyfriend). Prolonged exposure to it breaks the guests more and more. Both protagonists have completely lost their sanity by the end of the series.
• "Gyagu Manga Biyori" has the tale of the son and father who wanted to hire a tutor (and chose her more for the sake of her looks than the help she would give), but take many days to realize that they were tricked (Of course, like everything else, it is done in such a way that you have to laugh). At first they just look depressed when she doesn't show up, then their hands start bleeding because they clench their fists so hard and are beating the walls... their explanation for her absence is that they don't have a welcoming enough feeling in their home. Cut to them dressed as clowns as the father keeps stabbing a rock-hard cake while shouting "She won't come!" several times, mixed with laughter... It becomes an Inverted Trope when they then grab a hold of themselves and they work their way to becoming pure levitating Buddhists.
• Enrico Maxwell of Hellsing, who has never been the biggest bastion of morality in the series in general, goes off the deep end upon attaining the rank of Archbishop and being assigned a full army to stop Millennium's attack on London. Massively Drunk with Power and seething with hatred for every Protestant in London, upon his arrival, he orders his forces to kill not only Millennium, but everyone who Millennium hasn't already killed, a move which disgusts both Integra and his most loyal agent Alexander Anderson. His unbridled arrogance soon becomes abject terror when Alucard arrives and turns his full power and every one of his familiars upon both his forces and Millennium, revealing himself to be none other than Dracula in the process.
• The mother and father of sanity slippage: Kars from JoJo's Bizarre Adventure Battle Tendency. After attaining Ultimate Life Form status, he loses anything resembling sense. And once he's thrown into space, he goes so insane his brain shuts down.
• It is made fairly obvious that K's Fushimi Saruhiko was not born Ax-Crazy. But because Love Makes You Crazy and Yata Misaki is pretty dense he starts resenting HOMRA and defects to SCEPTER 4 because if Misaki hates him he will finally pay him some attention. Memory of Red and Days of Blue show clearly how much it pains him but even Misaki outright trying to figure this out did nothing to snap him out of it. It's rather tragic, especially when you see his Psychotic Smirk which, at the same time, is the happiest you'll ever see him.
• Kill la Kill has Nui Harime after getting her arms cut off. She drops her cute facade into something very disturbing and swears much more. Her song changes to an even more disturbing metal version after and she gains a Slasher Smile.
• Knight Hunters:
  • Youji Kudou begins slowly losing his mind after killing his would-be love interest before she could kill him first (although close scrutiny will reveal a few hints of it beforehand, such as a manga scene where he mistakes Omi for her after waking up from a nightmare). Before it's over, he's nearly killed several one-night stands and had several long conversations with the woman's ghost.
  • Ken Hidaka doesn't fare much better: starting with the two-part OVA Verbrechen ~ Strafe, he finds himself enjoying the act of killing more and more, goaded along by having to fake killing his teammates and having to actually kill his girlfriend when she turns into a target. He manages to avoid falling so far as to start killing people on his own time, but in the Radio Drama Fight Fire With Fire, set after Weiss has been dissolved, he tries to convince Aya to become the new Persia so that he'll have someone to tell him who he can kill.
• Koharu Mutsuki Koharu no Hibi acts more Yandere as the story progresses as a result of her love for Akira.
• In Mobile Suit Gundam SEED Destiny, Shinn Asuka descends into this. He starts out as a Jerk with a Heart of Gold with plenty of anger and depression issues thanks to the events of the first war, but the events of the series takes his toll on him — his headbutting issues with Athrun, his unhealthy relationship with Stella, his untreated war trama and inability to see in shades of gray towards people all affect him in some way. Stella's death and Athrun defecting break Shinn so that he effectively becomes The Brute for the series' true Big Bad.
• My Hero Academia:
  • Tomura Shigaraki tends to have fits of this when people annoy him too much or he doesn't get his way.
  • Class 1-B's Neito Monoma started off as a well-put schemer who looked down upon Class 1-A. After Bakugo defeated his team in the Sports Festival, Neito can't ever seem to stop belittling Class 1-A of anything they had done. He almost always is on the receiving end of Itsuka's Dope Slap to stop him from embarrassing their class, though.
• Naruto:
  • Itachi displayed this during his fight against Sasuke, while claiming that his true plan was to get Sasuke to awaken his Mangekyo Sharingan so he could use his eyes to replace his own, and suggests this is his true self. It actually isn't, as Sasuke later discovers.
  • Sasuke plays it straight, though. As if deciding to murder everyone in the Leaf Village weren't enough, he outright hits the floor in chapter 480 and the few after it. He's basically been reduced to a homicidal maniac who will kill anyone if they become the least bit inconvenient to him. Thankfully, he gets better, though it takes, amongst other things, a chance meeting with a reanimated Itachi and Naruto smacking some sense into him.
  • Orochimaru went through this in his backstory, but managed to conceal it enough that he'd already been kidnapping people for depraved experiments for ages when Sarutobi finally worked it out. Nagato went through something more like a Heroic BSoD that resulted in a Madness Makeover to Pain, but there was enough of a time spread that he definitely had time to devolve gradually. As Madness Makeovers go, wearing your murdered friend's corpse as a puppet avatar is pretty near the top.
  • Gaara qualifies for this from his flashbacks. As a kid he was initially sweet and misunderstood. Then his father started sending people he loved to assassinate him. Fast forward to his early teens, and he's a homicidal maniac talking to sand as though it's his dead mother. Luckily he recovered.
    • Although as it turns out he's pretty much right about the sand. His sand automatically shielding him is basically his mother's spirit moving to protect him from harm.
  • Kabuto lost quite a bit of sanity after Orochimaru died.
    • His backstory reveals that he suffered a significant dose of this when he was nearly killed by his mother figure, who in turn didn't recognize him. Increasingly unsure of his own identity after years as a spy, only Orochimaru's intervention stopped him from cracking.
• Neon Genesis Evangelion has a cast that displays their loss of sanity in different ways... some a little more disturbing than others.
  • End of Evangelion decides to do away with the incremental slips and jumps right off the edge thanks to the ritual to awaken Lilith leaving Shinji a shrieking broken mess.
• Odd Taxi: "Tanaka's Revolution" shows how this happened to the titular Tanaka. After a string of bad luck incidents in which he is essentially a Cosmic Plaything including losing millions in a gacha game only to then lose the pull he spent all that money looking for, this results in him snapping totally and becoming a man obsessed with revenge on someone who doesn't even know he exists.
• One Piece has Brook, whose lonely life after he was the only one of his crew to come back from the dead has plainly taken its toll.
• Ookami Kakushi: Issei in the few episodes he appears in until he dies in episode 5.
• Quite a few characters in PandoraHearts go through this at one point or another, like Leo after Elliot's death or Oz when he goes into Love Makes You Crazy mode for Alice. (He gets slapped out of it by Gil).
• Mima and Rumi of Perfect Blue both experience this. Mima gets better but Rumi doesn't.
• Poison Berry in My Brain: After she forcefully gets Ishibashi to leave, Ikeda deteriorates over the course of the final four chapters due to her excess power inside of Ichiko's head.
• In episode 7 of Puella Magi Madoka Magica, we can see Sayaka breaking down fast as she fights a witch. Why? Because a friend of hers had just told her that, in one day, she was going to confess to the boy Sayaka loved. That was just the last straw, though. Other factors certainly helped.
  • By the end of Rebellion, it's clear that Homura may very well have left her mind in that Flower Field. And that's not even getting into what Kyubey goes through.
• Makoto in RahXephon teeters on the edge until his grand scheme bites him in the ass, at which point he takes the thrilling plunge into insanity.
• In Romeo × Juliet, after witnessing his father Titus's death, Mercutio quickly starts losing it. And he ends up killing the murderer, Lord Montague, through quite the Karmic Death.
• In Saint Beast, Zeus becomes increasingly insane as the series progresses.
• Sekai and especially Kotonoha in the anime of School Days.
• Cool Big Sis Yuuri from School-Live! started slipping after the main characters left the school. It's implied she is hallucinating that a teddy bear is her little sister. Her instable mental health was foreshadowed earlier when she freaked out when she almost had to kill Kurumi when she was becoming a zombie and later when the rescue helicopter crashed.
• By the end of Serial Experiments Lain, most of the characters, major and minor, including to some extent, Lain herself.
  • Hell, it's implied to happen all over the world.
    Newscaster: Lets all love Lain! Lets all love Lain! Lets all love Lain LainLainLain!!!
• The Seven Deadly Sins: As the story begins to reach its conclusion, Estarossa's mental state rapidly deteriorates from Jerkass to full blown Ax-Crazy, even before he absorbs multiple Commandments. Justified, as on account of actually being a Goddess, not a Demon, Estarossa's body was never meant to hold even a single Commandment. He gained it not too long before he and the Demons got put into stasis, so from his point of view he only held it for barely over a week.
• Kaede from SHUFFLE!. In the anime version, anyway.
• Soul Eater:
  • Professor Stein goes completely insane as a result of Medusa's plans. He got better, but still the entire collection of scenes showing his descent into madness is creepy.
  • Sort of applies to Soul Eater as well, once he started using the black blood.
  • The entire cast is constantly teetering on the edge of this trope. Madness functions as The Dark Side in the Soul Eater universe, with characters falling into madness becoming evil and others resisting the temptation to madness. One of the major villains is someone who slipped so far into insanity that he became an Eldritch Abomination.
  • The manga-verse now holds that he's apparently insane because he's an Eldritch Abomination personifying a kind of madness. Same point reveals that Death the Kid is the next in line for slipping.
• In Stepping on Roses (Hadashi de Bara wo Fume), Nozomu, who at first seems like a really Nice Guy gradually becomes more and more of a psychotic Yandere as the series goes on.
• Takopi's Original Sin:
  • Shizuka's desperation to get Chappy back and see her father leads to a downward spiral of manipulation and spur-of-the-moment plans, culminating in an incident where she kidnaps her dad's other kids, thinking them impostors.
  • Azuma turns into a Love Martyr, willing to do anything Marina says at the cost of his own sanity out of fear he'll lose the only person who's shown him positive affection.
• Tengen Toppa Gurren Lagann has Simon going Ax-Crazy while fighting enemy mechas, locking himself on his room almost 24/7, and spending all his time carving statues of Kamina out of stone. Luckily, he finally does a 180° flip.
• Ikuya Asano from The Twelve Kingdoms falls into this due to him getting closer and closer to the Despair Event Horizon as he's Trapped in Another World.
• In Tokyo Ghoul there's Kaneki. After he is tortured by Jason, he has a major change in character. He becomes unfeeling towards most and kicks major butt. He is able to defeat not only Touka's brother, Ayato, but also Jason. A clear display of his changed personality is when Kaneki actually bit Jason. As he claims that he tasted like spoiled fish intestines, it was not for personal pleasure, but rather just to hurt Jason and show him that he wasn't the person he used to be. This not only proves his point, but also goes to remind Jason that he was the one who created this monster of him.
  • Tsukiyama has a psychotic break whenever somebody or even Kaneki himself tries to interfere in his eating Kaneki.
  • In chapter 79 Mutsuki has one. Upon discovering his crimes, Mutsuki begins laughing and screaming hysterically.
• Happens to Kish/Quiche in Tokyo Mew Mew. What starts off as a simple Villainous Crush soon turns into Mad Love. Towards the end of the series, he turns into an Ax-Crazy Stalker with a Crush who is Not Good with Rejection. This changes in the ending where Love Redeems.
• Ryu's Path: Condor wasn't born evil, but due to his infliction, he was Ax-Crazy by the time Ryu met him. Thankfully, he was able to restore his sanity and even brought him back from the dead to support his future missions.
• Trigun:
  • A bit in-continuity, but mostly during the SEEDs flashback, after Rem gets Vash and Knives out of the medbay where they learned the awful truth and promptly attempted to starve to death. Vash persists in wanting to die and hating humans, stabs Rem in the side in the course of a fight over a fruit knife he hopes to use on himself, and for a really awful moment, he smiles. Then he breaks down crying, patches her up, and things start to be okay again.
  • Notably, Knives didn't get this. Knives went promptly and utterly over to mad from the revelation, and acted like he'd blocked it out and was perfectly okay right up until enacting Plan Kill All Humans.
  • Legato also devolves steadily and horribly over the course of Maximum — yes, he was already bonkers, but after Knives breaks his spine he falls apart rapidly. Though he doesn't get less dangerous — after all People Puppets are his specialty.
• Millions Knives from Trigun Stampede, even moreso. With every appearance he makes, it becomes clearer that Knives's cold rationality in the present day is a front and he is in fact very emotionally unstable. His habit of laughing to himself, his odd facial expressions when he does emote, and his brief but explosive outbursts of rage do not paint a healthy picture of his mental state. When Vash throws off his control in episode twelve any appearance of stability crumbles and he's reduced to bellowing like an animal.
• Dilandau Albatou from Vision of Escaflowne is a subverted example. He was already kind of Ax-Crazy to begin with, but after Van slashed Dilandau's face with a sword in a Curb-Stomp Battle, Dilandau's already fragile state of mind went downhill from there.
• Yu-Gi-Oh!: In Transcend Game, Seto Kaiba uses his technology in an attempt to reach the departed Atem without much care for the fact the effort might kill him.
• Sora Shunnin of Yu Gi Oh ARCV was already something of a Creepy Child, but his match with Shun in the Maiami Championship took it to all new levels as he shows his true colors.

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