AKIRA: Tetsuo has always been treated as the runt of the Capsule gang and bullied by nearly everyone around him to the point of developing a severe inferiority complex. When his Psychic Powers manifest, things get very ugly very quickly, for both the Capsules and everyone around him.
City Hunter: A light-hearted version: Ryo mocks Umibozu at every chance he gets (the nickname Umibozu itself is part of it, as it means 'sea monster' and replaced both Umi's real name and previous codename Falcon), so when an hypnotist made Ryo believe he had a bigger penis he took the chance to mock him back, even running to Ryo's home to laugh in his face when rumors started saying that the loss in the penis contest had made him impotent. At the end of the story arc, the hypnotist was made impotent permanently.
Her own sister Sylvia whipping her in blame for her handicapped state? Ange gives her a harsh lesson during the finale of "Distorted World", showing she has to no right to blame anyone if she refuses to stand on her own two feet since her injuries are completely healed. She does this by pointing a gun at her and forcing her to get out of her wheelchair by threat of death.
And finally, about all of the humans who use Mana get this treatment. After an unknown amount of years for looking down on Norma for their inferiority of not being able to use Mana, Embryo considers the humans a liability and has them Brought Down to Normal. They end up resorting to cheap tactics to have Ange find them shelter. Ange's reaction to it? She leaves them to fend for themselves with Sylvia as their leader.
Subverted, averted and inverted in the span of only a few seconds in Death Note. After Light is revealed to be just a human with a note and a bunch of bullets in his chest, Mikami goes mad from the revelation, but instead of turning on him, (some say) stabs his arm with a pen (and kills himself in the process) to allow Light to run. Also Light takes good care to subvert this as much as possible with his other "doggies": he "writes in stone" everything Takada will do, leaving no chance for her to retaliate in any way and positively reinforces Misa to do anything he wants (otherwise he'd just kill her as fast as he could) and ultimately makes sure she won't bother him in his part of his life as Kira by forcing her to renounce her Note.
It's also played straight when Matsuda shoots Light after an entire series of trying to help but not being able to, after Light says he was manipulating Matsuda's trust the entire time. Light himself is shocked by that, having figured that Matsuda would be the one most loyal to him...
Subverted in Monster. Johann didn't need help to be a monster and he didn't care enough about his creators to take revenge. He kills them anyway.
Siri eventually gets to give Bride, a man who forced her into a cult "marriage" and tortured her constantly for several months, his comeuppance by holding him over the edge of a cruise liner by his arms as its sister ship slams up against it. Severed limbs ensue.
In Fullmetal Alchemist, Solf J. Kimblee gets his throat torn out by his ex-bodyguard Heinkel, who Kimblee almost killed twice during his battle with Ed and another with his brother Al.
Kimblee himself does this to Pride, who had absorbed his soul following his "death".
Dr. Marcoh also stuck it to Envy by laying out a trap with his travel partners, after Marcoh had been held captive with his home village as hostage. Envy went from One-Winged Angel to Clipped-Wing Angel once Marcoh was done with him.
Greed, after Father had previously killed his first incarnation and had just stolen him back from Ling's body by force to use his Philosopher's stone, returned the favor by reversing the effects of his Ultimate Shield to turn Father's body into brittle charcoal that would make him easy to kill.
In the end of the 2003 anime version, Dante was killed by Gluttony after she erased his memory to turn him into a mindless monster.
In Crows, Hideomi Kunou gets Yamazaki to sell out his friend Bandou, who gets his ass kicked before getting run over by a motorcycle. When everything falls apart for Kunou, Yamazaki returns to pay him back in kind.
Subverted in Toward the Terra. Keith Anyan is repeatedly abusive towards his subordinate Jonah Matsuka and informs him that once the war against the Mu is over, he'll be disposed of; he asks if Matsuka will kill him before that happens, apparently deliberately trying to needle Matsuka into doing just that. Instead, Matsuka sacrifices his own life to save Keith's - to Keith's considerable surprise and dismay.
In Pokémon Adventures, Blue really didn't appreciate being kidnapped and being forced to become someone's underling, so she swiped the Applied Phlebotinum on her way out escaping, setting back the Big Bad's (named the Mask of Ice) evil plot for several years, and actively looked for ways to take him down. Granted, she didn't deliver the finishing blow, but she was a big part of it nevertheless.
The anime likes doing this with the Fire type starters under Ash's care — Charmander and Pignite blasted their abusive former trainers with Flamethrower, while Chimchar evolved all the way to Infernape after being released by Paul and was the lone Pokemon left on Ash's side at the end of the Sinnoh League battle.
In the Pokémon Golden Boys manga, during Gold's encounter with Lapras, Black attempts to catch it...and decides to use Bayleef. Of course, Bayleef is defeated, and Black, in a fit of rage, tells it "You're so weak. I DON'T NEED YOU ANYMORE!!" This results in Gold taking Bayleef in. Later, in the Burned Tower, Black forces Gold to fight him using his weakened Haunter, taunting Gold when he hesitates in using Croconaw. Bayleef proceeds to angrily charge at Black and take Haunter out in a single blow.
Shadow: I came out of the Dark Mirror, and with its power woke you. How fitting that I use it to destroy us both!
In Digimon Adventure, Myotismon raised Gatomon as a minion but abused her on a regular basis. While she has some loyalty to him, it's ultimately destroyed when she discovered she had a choice in the matter and to be good; maybe if he'd treated her better recent events wouldn't have happened. Then he goes and kicks one dog too many and kills her best friend Wizardmon, resulting in Gatomon digivolving and killing Myotismon.
Wizardmon himself might count too as by the time he attacks Myotismon (from behind) drawing first blood it should added. Myotismon has abused his best friend as mentioned above, tried to drown him and presumably subjected him to the same abuse as all the other people who work for him.
Happens AGAIN with Myotismon at the end of Season 2. He possessed Oikawa to put Dark Spores inside some kids who think their dreams have been taken away, harvesting them to come back to life as MaloMyotismon. When the darkness is getting stronger and it seems MaloMyotismon has won, Davis says he wants to open a noodle cart and work hard on it, which causes the kids to speak of and regain their dreams, destroying Myotismon's body and setting the stage for his spirit form to be destroyed soon after.
In Sakura Gari, this is Tomohiko Katsuragi's perdition. The three persons whom he abused the most ( Masataka, Souma, and his own wife Asayo) are the ones who orchestrate the spectacularHumiliation Conga that he suffers and which finishes in a fiery Karmic Death.
Sakon Daimaru from Gamaran had his life and mental sanity ruined by his elder brother Ryuugo, who even yelled at him for losing his battle against Gama. This prompts Sakon to go insane and snap Ryuugo's spine as soon as he turns around.
In Soul Eater, Chrona stabs their mother, Medusa to death after all the nightmare-inducing experiments she ran on them.Although that's a bit misleading. They don't kill her because of how horrible she is, they did it because Medusa was suddenly acting like a real mother, such as cooking their favorite meal for them and apologizing for all the things she did, even hugging them. But Chrona is so insane from the experiments and so shocked by this that they assume that this is an impostor. And in the end? The last thing Medusa says in the chapter confirms that this was all part of her plan.
In Jack and the Beanstalk (1974), throughout the movie the witch Hecuba insulted and abused her son, the giant Tulip. Eventually he had enough; when she told him to finish Jack and Margaret, he chose to kill her instead, by stepping on her.
In the Red Ribbon Army Saga of the original Dragon Ball, Black, after narrowly surviving being knocked out of a window and being flattened (It Makes Sense in Context), overheard Commander Red's plan of wishing to Shenron to become taller. Black then confronts him on this, having earlier been led to believe, alongside the rest of the Red Ribbon Army, that the wish was meant to be for World Domination. After Red not only protests Black's accusations, but also Kicks The Dog one time too many by implying that the reason why Black's upset is that he's jealous that he isn't commander, and that he deliberately made Black an expendable lackey while also claiming that Black is pathetic even for that, Black decided that was the final straw and proceeded to execute him by shooting him in the head.
Similarly, Majin Buu in Dragon Ball Z gets tired of Babidi's verbal abuse and threats to seal him up. The result is predictable.
In Haou Airen, a boy named Kaafai is Forced to Watch as the Bastard Boyfriend lead, Hakuron, rapes his girlfriend Kurumi, whom Kaafai had befriended few hours ago. Guess who becomes a police officer and shoots Hakuron dead at the end of the series?
In The Big O, a kitten who became attached to the robot Dorothy is abducted and experimented on by a Mad Scientist after killing its original owners. Said kitten monster trashes Roger and his robot companion a bit before Dorothy helps it come to its senses, whereby it grabs the scientist goading it to kill Dorothy with its giant tentacle and snap his back offscreen.
Buhpu, having killed Ivy Cortlaw to manipulate her brother Kid into fighting the MLS by making him think they had killed her, gets killed by the one he had manipulated when the truth comes to light.
In a similar case, Teeki killed Enchu's mother, with the ultimate goal of taking Enchu's body, and Muhyo revealing the truth behind this results in Enchu resisting Teeki's possession and enabling Muhyo and Roji to finish Teeki off.
The ending of Puella Magi Madoka Magica can be seen as this. Kyubey doesn't directly hurt Madoka, but he sure doesn't hesitate to inflict horrible tragedy on her friends, with the intent of forcing her to make a contract no matter how much her life gets screwed up in the process. His over-the-top heartless abuse convinces Madoka, who had openly refused to given in for the entire series, to invoke Laser-Guided Karma on him and his entire species, and the entire universe via contracting and then turning her wish into something that totally screws with the Magical Girl System led by Kyuubey, sacrificing herself in the process and then ascending to pretty much god-hood to make sure that other prospect magical girls won't go through the same suffer.
Shown again in Rebellion.Kyubey's machinations end up causing Homura to gain godlike powers like Madoka... except she becomes the Devil to Madoka's God. And she has absolutely NO problem making Kyubey's life and that of his entire race a merry Hell. Everyone else is spared though.So to speak.
In Claymore, when Cassandra the Dust Eater was alive, she was massively screwed over by Roxanne of Love and Hate. Not only did Roxanne leave Cassandra's only friend amongst the Claymores to die at the hands of a youma, she also bashed Cassandra herself over the head when she tried to fight her way through a horde of Claymores to get her revenge, causing her to be cut down and killed. Fast forward some years later, and the two of them - along with Hysteria the Elegant - are resurrected by the Organisation and eventually awaken. After Roxanne uses up all her weapons fighting Cassandra and is rendered powerless, Cassandra happily chows down on her, giving her a well-deserved Karmic Death.
Detective Conan has this as many a cause of murder. The two examples below are just a small show:
In the Luxury Liner case, the artist Ichiro Hatamoto kills his grandfather Gozo after he getting fed up with the years-long abuse that the old man subjected him to. The cherry on top is when Gozo cruelly mocks him andrefuses to let him marry Natsue, the girl he loves, who also happens to be Gozo's granddaughter and Ichiro's cousin. When this happens, the until thenshy and unassuming Ichiro savagely snaps and stabs Gozo to death.
In a filler case, the Kimono Goddess legend tells that the Kimono Goddess once was a human girl named Ohana, whose angry spirit kills the two greedy local girls who caused her unfair death. Even more symbolically, their lifeless bodies are found surrounded by the luxurious kimonos that the two girls wanted enough to get poor Ohana, the real owner of said clothes, killed. And this is made more maningful when the long-lost sister of a Kimono Goddess legend devotée, who was Driven to Suicide by two rich bitches, invokes several motifs of the legend in itself as she kills them in revenge.
In Fairy Tail, Posthumous Character Karen Lilica had this happen to her in the backstory. She was a celestial spirit wizard who treated her celestial spirits as slaves. She went too far one day and one of her spirits rebelled against her and left her unable to use her magic. Although this left her defenseless, Karen was too proud to bow to the spirit's demands that she release him and another spirit she'd been abusing, and went on a job anyway. She was killed on that job.
In the seventh volume of Mekko Rarekko, Buchi becomes Amanuma's Sex Slave when Amanuma, a real Jerkass convinces him that he's Not So Different from Taishou his best friend who is also Amanuma's sex slave. Amanuma tortures Buchi and Taishou a lot but he is much crueler towards Taishou. When Buchi can't stand seeing Taishou tortured anymore, he tackles Amanuma and when he sees his smartphone, he stomps on it until it's destroyed. It also doubles as a literal The Dog Bites Back moment since every character in Mekko Rarekko is a dog (A Kemono dog.)
The villain of the CP9 saga, Spandam has spent the entire arc beating Nico Robin mercilessly without any way for her to defend herself, as well as saying anything he can to break her spirit. Once she ends up breaking free, she pins him down, smacks him in the face over and over, then finishes it off by snapping his spine nearly in two. This doesn't kill him, but it ends up making him suffer a Fate Worse than Death due to him being crippled for life while the group of assassins he was the former boss of is out for his blood. For a while, though, as he eventually recovered and is now in the CP0 but, ironically, two of said assassins are now his superiors.
Trafalgar Law's entire plan, including his alliance with the Straw Hats, has been to get revenge on Donquixote Doflamingo for an event in their shared past that occurred thirteen years ago. Doflamingo killed his own brother, Rocinante, who was Law's Parental Substitute and the man who pulled the Tyke-Bomb Law back from the brink and found a cure for his incurable disease while ensuring the kid's escape from Doflamingo, who wanted to be Law's Evil Mentor instead. Thus Law's singular focus is to make sure Doflamingo dies no matter what, even if it means he has to die as well in the process. Doflamingo doesn't die, but he is subjected to one of the series' most brutal Break the Haughty processes of the whole series, which more or less works anyway.
Kill la Kill: Satsuki stabs her mother Ragyo through the chest and announces a rebellion against COVERS in episode 17. A large part of Satsuki's hatred was caused by Ragyo killing her father and, some years prior, then using her baby sister as a guinea pig for Life Fiber experiments, then dumping said baby sister down a garbage chute — not to mention all the very creepy molestation she'd been subjecting Satsuki to since she was just a little girl. For bonus points, Satsuki is usually stoic, barely emoting outside of being annoyed and smirking, but, when she does the aforementioned, she makes no attempt at hiding her Unstoppable Rage.
Tokyo Ghoul makes use of this trope to triumphant and horrifying results.
Kureo Mado murders both of Hinami Fueguchi's parents, and engages in Evil Gloating when showing her the weapons made from their bodies. (Plus he had done the same to her mom Ryoko before killing her) He forces the poor girl to watch him use these weapons to torture her Cool Big Sis Touka, then mocks her over her grief and tries to kill them both. Hinami's kagune manifest for the first time, maiming him while she screams at him to not use her parents to hurt people.
After 10 days of brutal torture, Kaneki gives into his despair and fully embraces his ghoul powers. He breaks free from his chains, and proceeds to beat his torturer Yamori within an inch of his life. After devouring his kagune to render him helpless, Kaneki leaves him to die at the hands of the Ghoul Investigators currently invading the base. Not because he doesn't want Yamori dead, but because he's simply not worth Kaneki's time anymore.
Subverted by Juuzou, when confronting his abusive"Mama", Big Madam. While his mission involves hunting her down, he reassures her that he doesn't hate her.....and closes his eyes sadly while his squad finishes her off.
Taking to a horrifying degree with Mutsuki, who used an axe to murder his family after years of abuse from his father. After nearly a month being held prisoner by Saeki aka Torso, he snaps and tears the ghoul apart in a gruesome dose of Laser-Guided Karma.
Torso himself was the biting dog at some point, when as a youngster he used his powers to murder his abusive father after he killed his Only Friend.
Tatara probably should have restrained his Kick the Dog tendencies to avoid this trope. Instead, it comes back to bite him in full force when Takizawa betrays and kills him as revenge for being maimed, kidnapped, experimented on, raped, tortured, and forced to serve Aogiri.
Tsuneyoshi Washuu's habit of siring Bastard children as servants comes back to bite him, with two of them ( Arima and Furuta) leading separate plots against him. While both conspired to destroy the Washuus and their organization, their goals and methods in biting back were very different: Arima worked with Eto to create a revolution to free the world, while Furuta takes the direct route by murdering Tsuneyoshi and takes over the CCG, leading it down a path of open sadism and destruction.
The Neon Genesis Evangelion film End of Evangelion has this happen between Asuka and Shinji. After an entire series of belittling him, mistreating him, and insulting him at every opportunity, in EoE Shinji finally snaps and strangles the ever-loving crap out of Asuka.
Overlord (2012): One of the Workers is a proud slaveowner, who goes around with a trio of elf slaves he beats and rapes to keep in line who cast buff magic on him when ordered (and when one dies to enemy attack, his actions, or just malnutrition, he just gets a new one). When going up against Hamsuke, he ends up losing both hands and orders the elves to heal him... and suddenly, they're looking a lot happier. When Hamsuke caves the bastard's head in, they're seen kicking the corpse, and are later spared death by Ainz, who lets them stay in Nazarick to help take care of Aura and Mare.
In Chapter 31, Mamizou explains that while youkai have to make trouble for humans, they have to be careful not to actually hurt or kill anyone, lest they decide enough is enough and start seeking revenge.
In Chapter 32, Aya takes a zero-sum approach by explaining to Marisa that the reason youkai oppress the human villagers is because they believe that should they ever gain power, or if a leader figure shows up there, they'd take the fight to the youkai. Either case would probably end Gensokyo's relative and precarious peace for good.