History WeUsedToBeFriends / AnimeAndManga

* ''Manga/IganoKagamaru'': Kagamaru and Hayate were both orphans raised by the same man, Kagamaru's grandfather Saito Igano. Kabamaru considered him his best friend, and even their ninja skills were on par with one another. Come adulthood, and Hayate tells Kagamaru he was actually using his grandfather to escape from his past, and they should forget that they were ever brothers.

* ''Manga/{{X 1999}}'':
** Arashi Kishu. In order to spare her lover Sorata from his obligation to sacrifice himself for her, she joins the Dragons of Earth to bypass fate. She battles her former Dragons of Heaven friends and eventually [[SelfFulfillingProphecy triggers said prophecy]] with her FaceHeelTurn. In the anime, [[spoiler: Sorata dies anyway in her arms, but manages to make her return to the Dragons of Heaven.]] In the manga, by all appearances, [[spoiler: Arashi ends up BrainwashedAndCrazy at the hands of Hinoto's SuperpoweredEvilSide. With the same result, fighting for the Dragons of Earth. ]]
** More importantly, [[spoiler:Kamui and Fuma. They were best friends as children, and destined to be on opposite sides of the battle for the future of mankind. Whichever side Kamui chose, Fuma would automatically take the empty seat on the opposite side as a substitute "Kamui".]]
* Rivals Ash Ketchum and Gary Oak of ''Anime/PokemonTheSeries'' fame. They were good friends and neighbors when they were very young. It's explained that they fought over a Poké Ball they found and broke it, and stopped being friends over it. [[spoiler:It turns out each kept his half of the Poké Ball, and they are on better terms again by the end of Johto.]]

* In ''Anime/NeonGenesisEvangelion'', Ritsuko and Misato have been friends since college, but the events of the series causes rifts between the two, leading to frequent (and sometimes physically violent) arguments about how to handle situations which could endanger the pilots, and it doesn't help matters that Misato slowly comes to realize just how much Ritsuko has kept her in the dark about NERV's rather disturbing secrets. In the latter part of the series their relationship constantly teeters on the edge of fully turning into this trope, and it became pretty clear that Misato only stays on speaking terms with Ritsuko because there weren't too many others around to talk to any more. [[spoiler:What little that remained of their old friendship finally ends in Episode 23, as Ritsuko reveals the truth about Rei and destroys the Rei clones.]]
* ''Manga/{{Naruto}}'':
** Pretty much the whole point of Part II. Sasuke Uchiha is the patron saint of this. Even his new allies who were ready to give their lives for him were quickly discarded. What's interesting in this case is that Naruto's devotion to saving Sasuke - in one form or another - actually causes breaks between him and most of ''his'' friends, who think Sasuke is an [[ChronicBackstabbingDisorder evil back-stabbing bastard]] who needs to die, when they don't know how Sasuke came to truly be that way, when Naruto does, courtesy of Tobi. So essentially Sasuke has instigated a chain reaction of this trope.
** Even before that, we have Ino Yamanaka and Sakura Haruno stop being friends because they are competing over Sasuke (who doesn't much care for either one of them). They become friends again [[DesignatedGirlFight after fighting each other]] (which, at least to Sakura, was more about proving herself equal to Ino, whom she had held in high regard ever since she met her, than about Sasuke), but do still [[ContinuityNod quarrel over Sasuke from time to time.]]
** Jiraiya and Tsunade with Orochimaru. Jiraiya confronts Orochimaru during his escape from Konoha, and reminds them that the Sannin were friends since their team was formed when they were ''five years old'', but Orochimaru mocks his efforts.
** Oh, you can only imagine [[BrokenPedestal the look on]] [[spoiler:Kakashi Hatake]]'s face when it turned out that [[spoiler:Tobi, [[BigBad Public Enemy #1]] and the catalyst for nearly everything that's gone wrong in the verse]], was actually a NotQuiteDead '''Obito Uchiha'''. It doesn't help that [[spoiler:Kakashi was forced to kill Rin, [[LoveMakesYouEvil driving an onlooking Obito off of the deep end]].]] In spite of this, it seems that [[spoiler:Obito doesn't blame Kakashi for Rin's death, instead sticking by [[StrawNihilist his belief]] that the ''Naruto'' world is a CrapsackWorld; it could be argued that Obito's AssimilationPlot goal of creating "a world where heroes don't have to make pitiful excuses in front of graves" is being done for not only Rin's sake, but Kakashi's as well.]] It later turns out that Kakashi didn't [[spoiler:kill Rin. [[SuicideByCop She committed suicide by jumping in front of his attack.]] The Mist ninja had turned her into the Three Tails' host in the hopes of her becoming a TragicMonster and killing her village, so Rin enacted an HeroicSacrifice to ruin their plans and save her loved ones. Obito brushes it off due to his insanity-induced beliefs.]]
** In ''Naruto'', this goes way back to Hashirama Senju and Madara Uchiha. The latter, who is a ManipulativeBastard while being dead, had fantasized as a kid with the former about creating a place where children wouldn't be sent to die in war. As an adult, after temporarily giving his old dream a shot, he named the Hidden Leaf Village.
** In the [[Manga/Naruto1997 pilot]], Saburo and Kuroda, two fellow artists, were friends until the latter took over the former's job as head of the Council on Cultural Advancement, which resulted in [[KlingonPromotion Saburo stabbing Kuroda in an attempt to get the job back]]. Kuroda survived, but became cynical, bitter and unwilling to trust others. Saburo, [[MyGodWhatHaveIDone feeling guilty]] and apparently wanting to be friends again, painted his last work, "Symbol," as a symbol of trust and friendship, before [[DrivenToSuicide killing himself]].

* Miaka and Yui in ''Manga/FushigiYuugi''. Yui becomes Miaka's worst enemy after Nakago manipulates her into believing that Miaka doesn't care about her or her feelings for Tamahome. [[spoiler:In the end, Yui manages to redeem herself, and she and Miaka reconcile]].
* A major force of tension in ''Anime/MobileSuitGundamSeed'' is the fact that the two protagonists, Kira and Athrun, are best friends who have somehow wound up on opposite sides of a war. There is a great deal of introspection between the two of them about what this means to their friendship, how each other have changed, and why are they really fighting anyway? [[spoiler:Eventually they both decide to TakeAThirdOption and wind up as part of the Three Ships Alliance, on the same side once again.]]
* The second-gen story of ''Anime/MobileSuitGundamAGE'' revolves around Asemu Asuno and Zeheart Galette, who befriended each other when Zeheart (a Vagan) went undercover in Asemu's high school to find the Gundam (which is the Asuno family's raison d'etre). Soon enough, Zeheart reveals himself and returns to his side. He and Asemu are really conflicted about fighting each other, end up working together to prevent a ColonyDrop, [[spoiler:but in the third generation Zeheart goes over the edge and only reconciles with Asemu during a fatal duel that Asemu wins]]. An [=OVA=], ''Memory of Eden'', was made to further expand the Asemu--Zeheart story.
* ''Manga/MuhyoAndRoji'':
** Muhyo and Yoichi with Enchu. The three were close friends in the academy, but Muhyo and Enchu were considered for the position of Executor; Enchu was desperate to get the position so that he could support his sick mother while Muhyo didn't want it. Enchu losing his mother and the position in quick succession was his StartOfDarkness, as he became obsessed with revenge against Muhyo.
** Page and Tomas used to be friends before Tomas's evil nature became apparent, since Tomas was a notorious criminal even before coming to teach at the MLS alongside Page.
* [[spoiler:Mariko and Aya]] in the anime of ''Manga/DearBrother''. [[spoiler:They got along in junior-high, but one day Aya threw Mariko under the bus in a school competition, and things never were the same from then on.]]
* In ''Anime/MyHime'', Shiho and Mai got along well early on in the series, with Shiho asking Mai to [[ShipperOnDeck root for her attempts to win Yuuichi over]]. Midway through the show, however, Yuuichi tells Mai he has feelings for her with Shiho in earshot, and Shiho accuses Mai of lying to her [[spoiler:and tries to kill her when her Hime powers awaken, even going so far as to ''kill Mai's younger brother out of spite'']].

* In ''Manga/FistOfTheNorthStar'', a lot of the ManlyTears shed when Kenshiro and Raoh fight are because they both know that they can only win by killing their brother. Even when Kenshiro is ultimately victorious, he chooses to remember Raoh as the beloved brother he used to be.
** The series basically began on this trope. The StarterVillain of the series was Shin, a former friend of Kenshiro's, who in a mix of insanity, corruption by later villain Jagi, and vying for Ken's fiancee Yuria, gave Kenshiro his well-known seven scars on his chest, then strong-armed Yuria into his palace, under threat of killing Kenshiro. Later, Rei faces off against arch-enemy Yuda - both of whom trained in the art of ''Nanto Seiken'' together.
* The third drama CD for ''Anime/PuellaMagiMadokaMagica'' showed that Mami and Kyouko, who were shown together in the series itself for all of two scenes ([[spoiler:either in alternate timelines or after Madoka erased all witches]]) used to be close in something like a Senpai-Kohai relationship before [[PaterFamilicide a very personal tragedy befell Kyouko]], which soured her personality so much she left. In ''[[Manga/PuellaMagiMadokaMagicaTheDifferentStory The Different Story]]'', Mami and Kyouko do interact, as [[spoiler:Mami lived longer than in canon]], and things are largely awkward because of their differences, although they do still care for each other.
--> '''Kyoko:''' To me you're Mami Tomoe... [[spoiler:the only... family I got left!]]
** This is also true of [[spoiler:Homura and every single one of the main characters, due to the time loops]]. As was alluded to in the manga, and due to extreme PTSD after all that she had to suffer through, she is rather hostile toward and pretty much can't stand Mami and Sayaka, due to both of them [[spoiler:being the people most frequently responsible for driving Madoka into contracting with Kyubey]]. It's at the point where she doesn't even try cooperating with them and rejects Mami's overtures during their first few encounters, though the events of Rebellion indicate that there are still some residual feelings there, as [[spoiler:Homura can't bring herself to shoot a 'defenseless' Mami's soul gem during their big shootout]].

* Fushimi and Yata of ''Anime/ProjectK'' were once extremely close best friends until joining up with HOMRA. After that Fushimi became increasingly uncomfortable in his new surroundings and the fact that Yata didn't notice did little to help. Eventually his frustration and [[GreenEyedMonster jealousy]] of Yata's new found friends lead him to leave HOMRA and completely destroy his relationship with Yata in the process. Now the two of them do nothing but fight if they so much as see each other, though it's made very obvious that it's not really what either of them wants.
* ''Manga/FairyTail'' and its sidestory ''Fairy Tail Zero'' reveals that Mavis Vermillion, Fairy Tail's first Guildmaster, and [[spoiler:Black Mage Zeref]] were friends once. Mavis was the first person to show the latter kindness in a long time, and he was so moved that he taught her and her friends magic. In the present day, [[spoiler:Black Mage Zeref]] has succumbed to the negative feelings festering in his heart for centuries and has decided to wipe out humanity. Mavis seems to still feel sympathy for him, but does not hesitate to respond to his threat with a DeathGlare and a threat of her own that Fairy Tail will be the ones to wipe him out. As it turns out, the situation is a lot more complicated than orginally shown. [[spoiler:Mavis and Zeref were not just friends -- they were ''lovers''. However, it was Mavis's death that drove Zeref into the darkness. While Mavis still clearly loves him and empathizes with his situation, she also recognizes that he must be stopped and doesn't hesitate in aiding Fairy Tail in opposing him]].
** There's something of a three-way version of this between Erza, Jellal and their fellow slaves at the Tower of Heaven. After they managed to overthrow their captors, Erza saved Jellal, but learned that he'd been brainwashed into wanting to resurrect Zeref.[[note]]He's actually not dead, but that's beside the point here.[[/note]] Jellal allows Erza to leave, but does so while threatening to kill their other friends if she tries to do anything to stop him, while simultaneously deceiving the others into thinking she betrayed them by destroying their escape ship. Years later, Jellal finishes building the tower and has his other friends kidnap Erza to use her as a sacrifice, but she manages to get them to see the truth, and Simon sacrifices himself to save Erza. Now, the situation's reversed, with Erza reconciling with her friends and forgiving Jellal after seeing him [[TheAtoner work to atone for his crimes]], while her old friend Millianna teams up with Simon's younger sister Kagura to get revenge on Jellal.
* ''Manga/WanderingSon'':
** Takatsuki and Nitori become friends at the start and grow into PlatonicLifePartners over the course of the series. They're best friends and know each other better than anyone else. However this perfect friendship starts dying once they begin going to separate high schools. Eventually it comes to the point where they barely interact anymore. Takatsuki is surprised by how grown up Nitori has become after several months, if not years, of not seeing each other.
** After a falling-out over a LoveTriangle, Saori stops being friends with both Takatsuki and Nitori at the start of middle school. It isn't until near the end of middle school that their friendship recovers.
* ''Anime/VividStrike'': Fuka and Rinne grew up in an orphanage together, but Rinne's adoption by a rich family made her cold and aloof (this wasn't the actual reason for the change, but Fuka was under the impression that it was). This led to their falling out about a year before the story picks up when Fuka confronted Rinne about her treatment of one of her opponents in a martial arts match. What makes this notable is that it is a rare occasion in the entire ''Franchise/LyricalNanoha'' franchise (which runs on ThePowerOfFriendship and people being HappilyAdopted) that a friendship is shown to fall apart. [[spoiler:Luckily, in the end, Fuuka gets through to Rinne, and they eventually reconcile]].
** In ''Anime/MagicalGirlLyricalNanohaStrikers'', Regius Gaiz and Zest were two friends in the TSAB's Ground Forces who were frustrated with a lack of resources available to their branch of the Bureau, so Regius decided to work his way up the ranks and do something about it. Unfortunately, Regius became increasingly corrupt in the process, as well as complicit with the TSAB's darker side. After Zest and most of his subordinates were killed during an attack on [[BigBad Jail]] [[MadScientist Scaglietti's]] base, Zest's clone, who had all the original's memories, sought Regius out for answers as to why he became the person he is today. Their friendship never recovered, but Zest was shocked when Regius died at the hands of Due.

* ''Manga/YuriIsMyJob'' has Hime and Mitsuki. After Hime transferred to Mitsuki's school in fifth grade, the two became friends, since Hime, who wanted to be loved by everyone, was one of the few people who was interested in spending time with the overly serious Mitsuki. The two girls practiced together on the piano to play an accompaniment for the recital together, but rumors began to spread that Mitsuki bullied Hime into playing with her, since Hime had lied to her classmates and said that she couldn't play the piano. Hime ended up quitting the recital, but [[PoorCommunicationKills didn't tell Mitsuki about it]], which, combined with Hime's habit of telling lies, caused Mitsuki to no longer trust her. Mitsuki then told Hime's other friends about her habit of lying, resulting in Hime becoming a pariah in the school until she graduated, and Mitsuki soon transferred out. The two parted on bad terms, and only met by chance in high school, when Hime ended up working at the same salon where Mitsuki worked.

* ''Manga/KaguyaSamaLoveIsWar'':
** Hayasaka's mother Nao once served as Kaguya's older brother Unyo's valet, and the two are implied to have been just as close as Kaguya and Hayasaka are currently. [[spoiler:Unlike Kaguya, he wasn't able to forgive her when he learned she was spying on him at the behest of his eldest brother Oko, and her betrayal is why he grew up to be the {{Jerkass}} that he is in the present day.]]
** Downplayed with [[spoiler:Ishigami and Iino]] who were more acquaintances than friends seeing as they never hung out, though they got along well and looked out for each other. [[spoiler:Had things continued on that course, it's likely that they would have already been dating by the time the series started (Iino's best friend Osaragi was even convinced at the time that the two would be the perfect couple). Then the incident with Otomo happened, and when Iino directly confronted Ishigami hoping for some answers, [[SilentScapegoat he coldly refused to comment]], creating a rift between them that wouldn't mend until well into their shared term on the student council over a year later.]]

* The third drama CD for ''Anime/PuellaMagiMadokaMagica'' showed that Mami and Kyouko, who were shown together in the series itself for all of two scenes ([[spoiler:either in alternate timelines or after Madoka erased all witches]]) used to be close in something like a SenpaiKohai relationship before [[PaterFamilicide a very personal tragedy befell Kyouko]], which soured her personality so much she left. In ''[[Manga/PuellaMagiMadokaMagicaTheDifferentStory The Different Story]]'', Mami and Kyouko do interact, as [[spoiler:Mami lived longer than in canon]], and things are largely awkward because of their differences, although they do still care for each other.

* The third drama CD for ''Anime/PuellaMagiMadokaMagica'' showed that Mami and Kyouko, who were shown together in the series itself for all of two scenes ([[spoiler:either in alternate timelines or after Madoka erased all witches]]) used to be close in something like a SempaiKohai relationship before [[PaterFamilicide a very personal tragedy befell Kyouko]], which soured her personality so much she left. In ''[[Manga/PuellaMagiMadokaMagicaTheDifferentStory The Different Story]]'', Mami and Kyouko do interact, as [[spoiler:Mami lived longer than in canon]], and things are largely awkward because of their differences, although they do still care for each other.

** The series basically began on this trope. The StarterVillain of the series was Shin, a former friend of Kenshiro's, who in a mix of insanity and vying for Ken's fiancee Yuria, gave Kenshiro his well-known seven scars on his chest, then strong-armed Yuria into his palace, under threat of killing Kenshiro. Later, Rei faces off against arch-enemy Yuda - both of whom trained in the art of ''Nanto Seiken'' together.

** This is also true of [[spoiler:Homura and every single one of the main characters, due to the time loops]]. As was alluded to in the manga, and due to extreme PTSD after all that she had to suffer through, she is rather hostile toward and pretty much can't stand Mami and Sayaka, due to both of them [[spoiler:being the people most frequently responsible for driving Madoka into contracting with Kyubey]]. It's at the point where she doesn't even try cooperating with them and rejects Mami's overtures during their first few encounters, though the events of Rebellion indicate that there are still some residual feelings there, as [[spoiler:Homura can't bring herself to shoot a 'defenseless' Mami's soul gem during their fight]].

* In ''Anime/NeonGenesisEvangelion'', Ritsuko and Misato have been friends since college, but the events of the series causes rifts between the two, leading to frequent (and sometimes physically violent) arguments about how to handle situations which could endanger the pilots, and it doesn't help matters that Misato slowly comes to realize just how much Ritsuko has kept her in the dark about NERV's rather disturbing secrets. In the latter part of the series their relationship constantly teeters on the edge of fully turning into this trope, and it became pretty clear that Misato only stays on speaking terms with Ritsuko because there weren't too many others around to talk to any more. [[spoiler:What little that remained of their old friendship finally ends in Episode 23, as Risuko reveals the truth about Rei and destroys the Rei clones.]]

* ''Anime/SakuraQuest'' has Ushimatsu Kadota and Chitose Oribe, respectively the head of Manoyama's tourism board and a local confectioner. At first glance, it seems as though they don't get along due to their similarly grumpy personalities and butting heads over work, since Chitose opposes some of Ushimatsu's plans for being impractical or causing trouble for local merchants like herself. It later turns out that they knew each other when they were young and were close. [[spoiler:The two of them played in a band with their mutual friend and the town's mechanic, until Chitose came up with a plan to run away to Tokyo and play there to get more of an audience. Ushimatsu ended up getting cold feet, wanting to help awaken the town from complacently being stuck in tradition, so Chitose ended up abandoning her plans]]. It's implied that Chitose is still bitter about the incident, although she does seem to care for him for a certain extent. By the end of the series, Ushimatsu has apologized for the incident, and Chitose, who'd previously been critical of the tourism board's plans, unhesitatingly decides to support the Mizuchi Festival.

* Rivals Ash Ketchum and Gary Oak of ''Anime/{{Pokemon}}'' fame. They were good friends and neighbors when they were very young. It's explained that they fought over a Poké Ball they found and broke it, and stopped being friends over it. [[spoiler:It turns out each kept his half of the Poké Ball, and they are on better terms again by the end of Johto.]]

** Page and Tomas used to be friends before Tomas's evil nature became apparent.

* ''Anime/SakuraQuest'' has Ushimatsu Kadota and Chitose Oribe, respectively the heads of Manoyama's tourism board and a local confectioner. At first glance, it seems as though they don't get along due to their similarly grumpy personalities and butting heads over work, since Chitose opposes some of Ushimatsu's plans for being impractical or causing trouble for local merchants like herself. It later turns out that they knew each other when they were young and were close. [[spoiler:The two of them played in a band with their mutual friend and the town's mechanic, until Chitose came up with a plan to run away t Tokyo and play there to get more of an audience. Ushimatsu ended up getting cold feet, wanting to help awaken the town from complacently being stuck in tradition, so Chitose ended up abandoning her plans]]. It's implied that Chitose is still bitter about the incident, although she does seem to care for him for a certain extent.

* In ''Anime/MaiHime'', Shiho and Mai got along well early on in the series, with Shiho asking Mai to [[ShipperOnDeck root for her attempts to win Yuuichi over]]. Midway through the show, however, Yuuichi tells Mai he has feelings for her with Shiho in earshot, and Shiho accuses Mai of lying to her [[spoiler:and tries to kill her when her Hime powers awaken, even going so far as to ''kill Mai's younger brother out of spite'']].

* ''Manga/AoNoFlag'': A strange case with Touma and Taichi. They never became hostile towards each other, but as Touma grew popular and surrounded by people, men eager to be his friend and women eager to date him, several of which were implied to dislike Taichi, the two simply drifted apart as time went on and Taichi started feeling unworthy of Touma's friendship, chapter 16 reveals that this was partly because he fell in love with a girl that fell for Touma instead. The manga follows the story from the point they start to rekindle their old friendship, which Touma has been heavily implied to have always wanted to hold on to, [[spoiler:though he seems to have wanted more than just friendship.]]

* In ''Webcomic/AxisPowersHetalia'' we have America and England. Theirs is an interesting case, because even though America betrays England, it's done for political reasons, not because he hates him, and England is [[BreakTheCutie broken]] by it, but can't bring himself to kill him because he still loves him. Then, after hundreds of years they start to mend their bond. The [[{{Shipping}} shippers]] are not shy about what they think of all this.

* ''Manga/{{Berserk}}'': Guts and Griffith were close when they fought together in the Band of the Hawk during the Hundred Years' War. Guts deeply admired Griffith for the ambition of his dreams, and Griffith held Guts in greatest confidence by sharing parts of his personality that he would never show to his other followers. Things started to fall apart when Guts overheard Griffith saying he did not consider any of his followers "friends", as to him a friend was someone who would pursue a dream even if it meant opposing him. Guts took that as his cue to leave (so as to be able to stand next to Griffith as an equal). This led to Griffith making his career-ending TragicMistake. By the time Guts returned and helped the Hawks rescue Griffith, he all but despised Guts, using his hatred and despair to trigger the Eclipse and [[MoralEventHorizon sacrifice his comrades before doing horrible things to Guts and Casca both as his first act upon becoming a demon god]]. From then on, Guts saw Griffith as his hated ArchNemesis, while Griffith claimed to feel ''[[LackOfEmpathy nothing]]'' for Guts or anyone else.

* ''Manga/PandoraHearts'': Jack Vessalius and Glen/[[spoiler: Oswald]] Baskerville during the Tragedy of Sablier. [[spoiler: Upon learning that Jack tried to sink the world in the Abyss, Oswald tries to kill him, only to be killed himself by Jack. ]] In present day, [[spoiler: neither of them have forgotten their conflict, or their broken friendship.]]

* [[spoiler:Mariko and Aya]] in the anime of ''Manga/OniisamaE''. [[spoiler:They got along in junior-high, but one day Aya threw Mariko under the bus in a school competition, and things never were the same from then on.]]

** Oh, you can only imagine [[BrokenPedestal the look on]] [[spoiler:Kakashi Hatake]]'s face when it turned out that [[spoiler:Tobi, [[BigBad Public Enemy #1]] and [[TheHeavy the catalyst for nearly everything that's gone wrong in the verse]], was actually a NotQuiteDead '''Obito Uchiha'''.]] It doesn't help that [[spoiler:Kakashi was forced to kill Rin, [[LoveMakesYouEvil driving an onlooking Obito off of the deep end]].]] In spite of this, it seems that [[spoiler:Obito doesn't blame Kakashi for Rin's death, instead sticking by [[StrawNihilist his belief]] that the ''Naruto'' world is a CrapsackWorld; it could be argued that Obito's AssimilationPlot goal of creating "a world where heroes don't have to make pitiful excuses in front of graves" is being done for not only Rin's sake, but Kakashi's as well.]] It later turns out that Kakashi didn't [[spoiler:kill Rin. [[SuicideByCop She committed suicide by jumping in front of his attack.]] The Mist ninja had turned her into the Three Tails' host in the hopes of her becoming a TragicMonster and killing her village, so Rin enacted an HeroicSacrifice to ruin their plans and save her loved ones. Obito brushes it off due to his insanity-induced beliefs.]]

* ''Manga/{{X1999}}'':

* Ash Ketchum and Gary Oak of ''Anime/{{Pokemon}}'' fame. They were good friends and neighbors when they were very young. It's explained that they fought over a Poke Ball they found and broke it, and stopped being friends over it. [[spoiler: It turns out each kept his half of the Poke Ball, and they are on better terms again by the end of Johto.]]

* ''Manga/YuriIsMyJob'' has Hime and Mitsuki. After Hime transferred to Mitsuki's school in fifth grade, the two became friends, since Hime, who wanted to be loved by everyone, was one of the few people who was interested in spending time with the overly serious Mitsuki. The two girls practiced together on the piano to play an accompaniment for the recital together, but rumors began to spread that Mitsuki bullied Hime into playing with her, since Hime had lied to her classmates and said that she couldn't play the piano. Hime ended up quitting the recital, but [[PoorCommunicationKills didn't tell Mitsuki about it]], which, combined with Hime's habit of telling lies, caused Mitsuki to no longer trust her. Mitsuki then told Hime's other friends about her habit of lying, resulting in Hime becoming a pariah in the school until she graduated, and Mitsuki soon transferred out. The two parted on bad terms, and only met by chance in high school, when Hime ended up working at the same salon where Mitsuki worked.

* Miaka and Yui in ''Manga/FushigiYuugi''. Yui becomes Miaka's worst enemy after Nakago manipulates her into believing that Miaka doesn't care about her or her feelings for Tamahome.

* From what's seen in flashbacks, Tohru and Elma from ''Manga/MissKobayashisDragonMaid'' used to be rather close and traveled together for several decades. By the time the story starts, they are fierce rivals who hate each other due to problems caused by Elma's gluttony. That said, Kobayashi is convinced that they're still friends ([[VitriolicBestBuds just a different kind]]) and the first chapter of Elma's SpinOff reveals that she wishes to rekindle their friendship. [[spoiler:They manage to mend their friendship in chapter 64.]]

** In ''Naruto'', this goes way back to the First Hokage and Madara Uchiha. The latter, who is a ManipulativeBastard while being dead, had fantasized as a kid with the former about creating a place where children wouldn't be sent to die in war. As an adult, after temporarily giving his old dream a shot, he named the Hidden Leaf Village.

* ''Anime/VividStrike'': Fuka and Rinne grew up in an orphanage together, but Rinne's adoption by a rich family made her cold and aloof (this wasn't the actual reason for the change, but Fuka was under the impression that it was). This led to their falling out about a year before the story picks up when Fuka confronted Rinne about her treatment of one of her opponents in a martial arts match. What makes this notable is that it is a rare occasion in the entire ''Franchise/LyricalNanoha'' franchise (which runs on ThePowerOfFriendship and people being HappilyAdopted) that a friendship is shown to fall apart.

* In ''Anime/NeonGenesisEvangelion'', Ritsuko and Misato had been friends since college, but the events of the series caused rifts between the two, leading to frequent (and sometimes physically violent) arguments about how to handle situations which could endanger the pilots, and it doesn't help matters that Misato slowly came to realize just how much Ritsuko kept her in the dark about NERV's rather disturbing secrets. In the latter part of the series their relationship constantly teetered on the edge of fully turning into this trope, and it became pretty clear that Misato only stayed on speaking terms with Ritsuko because there weren't too many others around to talk to any more. [[spoiler:What little that remained of their old friendship finally ends in Episode 23, as Risuko reveals the truth about Rei and destroys the Rei clones.]]