- The Azula Trilogy has Azula become this gradually. At the start of the fic she is as selfish and arrogant as ever upon regaining her memory, though she slowly begins to develop a conscience when she allows the two Fire Nation peasants who found her after escaping the asylum to escape. Her Character Development continues when she convinces Zuko to allow her permission to find their missing mother, culminating with her giving a Shut Up, Hannibal! moment to her hallucination of Ozai, representing the darker half of her conscience. Azula's HeelFace Turn is then complete when she aids Team Avatar in liberating Ba Sing Se from Jian Chin's forces and resisting the temptations of the Spirit of War Zhan Zheng.
- This is one of the primary reasons behind Cassandra Cain's conversion to Christianity in Angel of the Bat.
- In For Good, Warp Darkmatter deals with some heavy guilt following his HeelFace Turn, and works hard to rid himself of it.
- Carpetbaggers, a Narnia fic, features a wolf named Rhea, who dedicates her life to serving the Pevensies in their new roles as kings and queens in order to atone for the evil deeds of her littermate Maugrim and the rest of her former pack who served the White Witch.
- The CLANNAD fanfic An End to All Things features an Okazaki that appears to be atoning for something, and it's implied that it's at least partially for his past self nuking the city at some point in the future.
- In Neither a Bird nor a Plane, it's Deku!, Izuku initially feels that the only way he could make up for nearly killing Bakugou as a child is to swear off his dream of becoming a Hero so he wouldn't hurt anyone else. His goal shifts to making up for all the trouble and hysteria he caused by arriving and living on Earth after All Might convinces him to follow his dreams again.
- In Child of the Storm, Loki sees his membership on the Avengers as atonement for his actions while insane.
- Bucky Barnes/The Winter Soldier, after being freed from his decades-long brainwashing during the first book's Final Battle, seeks to make amends for his all the evil he's done over the years. Though he also freely admits his belief that he'll never actually finds redemption for his actions.
- In Thousand Shinji, Rei was so jealous of Asuka and so furious with Shinji and her that she refused to help her fellow pilots several times. As a result, several of her friends got crippled or killed, Shinji and Asuka spent several weeks in a coma, and Rei was so sorry for everything and determined to make amends that she became this.
- Kingdom Crossovers: Zim went through a My God, What Have I Done? moment before the story started and he is now this.
- One of the major reasons why Legend comes to Brockton Bay.
- Also heavily implied to be the main reason Tattletale turns herself in to the authorities to make up for all the damage she's caused, especially to Taylor.
- Emma after a number of therapy sessions and eight months in prison.
- A number of former antagonists caught up in The Infinite Loops will take this role.
- The Doki Doki Literature Club Loops gives this motivation to Monika, and thoroughly explores the consequences of both her actions and her attempts to make up for them.
- In Justice League: The Spider, Spider-Man convinces the other six founding Leaguers not to fire Hawkgirl so that she can redeem herself by working with the rest of the League.
- Viper, Spider, Phoenix: O-Ren Ishii became a doctor and reinvented herself as "Joan Watson" to atone for her past as a yakuza boss.
- SAPR: Sunset Shimmer eventually evolves into this, though there is no single moment that flips her.
- People Like Us: Travis is deeply ashamed over his behavior and actions back in '76, and rather than acting like a crusader in the present he'd much rather keep a low profile while occasionally helping people through small gestures of kindness, hence why he gives Arthur a hand in the beginning.
- Cinders and Ashes: the Chronicles of Kamen Rider Dante: Hoshi, prior to the beginning of the story, wrote a fanfic about his Original Character beating up minions of an organization called Re:Shocker that represented people who harassed a departed friend of his. He soon ends up recieving the power of his character and soon finds out about what he wrote. This, along with creating a villain based off another friend who he was angry with at the time, led to him realizing his role in the conflict and vow to defeat Re:Shocker.
- Light in the Death Note fic Fever Dreams after he realizes the Kira plan isn't working and that he doesn't really want L dead.
- Light is this in AU Ragnarok, even though he's never acted upon his impulses he realizes he very nearly went insane as a teenager and was "a future Serial Killer in the making" and works to make up for it every day.
- Misa Amane in Silent Partner, Unfinished Business resolves to catch Kira so that he can be supervised and prevented from making any more "mistakes" and atone for the wrongs he's already done. Her need to make up for her previous love of Kira and her actions as the Second Kira grows through the course of the story.
- Ken in An Unseen Kindness wanders the digital world trying to make up for what he did in the events of the first fic in the series.
- Oikawa in the Zero 2: A Revision version realizes his own mistake after Cody's grandfather called him out for making a deal with Demon who enters the Real world along with threatening to shoot Hiroaki's wife for the Digivice and decides to try and make up for it by travelling to the Digital World along with Blackwargreymon and helps the other troubled Digimons in the process.
- In the Dragon Age: Inquisition fanfic Walking in Circles, Solas is this to Evelyn. Hes extremely protective and considerate toward her both out of love and guilt because, as he puts it, most of her ordeals and traumas were all or partially his faults and hes murdered her twice over with his mistakes.
- One of the Otswick's Templars, Ser Ralston, is also one. In his younger days, he had a dalliance with a mage as perk of the job, said relationship produced a child who was taken away but he kept an eye on her. But eventually, his child turned out to be a mage and didnt survive her Harrowing. He now spends the rest of his life atoning for his sin by helping and protecting mages whenever he can.
- The Dragon Ball Z Fan Fic Honor Trip has Perfect Cell as The Atoner in an alternate universe where Gohan doesn't kill him at the Cell Games, but instead scrambles his programming with a blow to the head.
- Crow in The Tainted Grimoire took part in several crimes and was a member of Khamja, a criminal organization. He had a HeelFace Turn and is now trying to make up for what he did.
- An unusually forward-thinking Omnicidal Maniac, Harry in Harry Potter and the Rest of the Sentence already has plans to beat himself over what he's done, once he's done doing it."Everyone was going to die. Everybody. And then he would pay for all the evil dark shadows beneath his misery. He would be promptly paying, with much longer pain."
- The premise of The Peace Not Promised is that after his death, Severus Snape is shown his many regrets - most especially his culpability for Lily's death, but also an assortment of murders, torture, and general debauchery, during his time as a Death Eater, plus his inability to keep Harry alive in the end - and is given a chance to go back and avoid most of them. He accepts in hopes of keeping Lily alive this time; everything else is secondary.
- Tai Lung in A Different Lesson doesn't start out this way—when he's not still being his arrogant, nasty, egotistical self, he's settled into a cross between Villainous BSoD and Despair Event Horizon over the ruin his life has become and his humiliating defeat by Po. But once he realizes everyone was right about him, and it truly sinks in what all he has done (and in the end, for nothing), the guilt and shame do urge him to follow this trope. Late in the story he proves he's come to understand what most Atoners do, when contemplating Xiulan, a woman whose husband he killed during his rampage: "He would spend the rest of his life trying to make it up to her."
- In The Blue Dragon, Malefor feels guilty of the past actions he did in the past, and throughout the story, atones for them.
- In the Mai Hime fanfic The Sword of the Lord, Nao and Reito are driven by a desire to atone for their actions in the Hime carnival. Nao despises Shizuru for apparently not doing the same.
- In Mega Man: Defender of the Human Race, Drill Man, ProtoMan, and Mr. Black are all these.
- those hardest to love need it most has Aizawa and Nedzu teaming up to take down Aldera Junior High after discovering how the staff enabled and participated in Bakugou abusing Midoriya.
- Nedzu specifically refers to this as making amends for past mistakes; while he was aware that Izuku used to be Quirkless, he drastically underestimated the impact this had on him, being blissfully unaware of how much discrimination the Quirkless face. Learning the extent of what they endure proves to be a sobering experience for him, and he sincerely regrets not taking it seriously.
- Aizawa, meanwhile, learns that he was Locked Out of the Loop because of his history of dismissing students based on his estimate of their potential. Nedzu assumed that if he knew about Izuku's past, he'd have kicked him out for his inexperience - and given that Aizawa was already planning to boot him out on that first day for being 'reckless' with his Quirk, he can't entirely claim that he was wrong. Aizawa also discovers that his tendency to call Izuku 'Problem Child' reinforced his student's surety that he was no different from the teachers he was used to dealing with - that he sincerely despised and wanted nothing to do with him.
- The reason why Bakugo in Waiting is worth it stays friends with Izuku in this continuity is because he feels horrible guilt for putting Izuku in his wheelchair, becoming overprotective to the point where people think that he has a crush on Izuku. Whether he does or not depends on whos reading.
- In many My Little Pony: Friendship Is Magic fics, Princess Luna, formally Nightmare Moon, becomes this after turning back to good after being banished to the moon for a thousand years which, as of season 2, is offically canon.
- Ancient Sins: After Dante reforms and joins the main cast as a hero of Equestria, he tries all he can to atone. However, unlike other villains, his road to redemption is very long and hard, but Dante is immensely pig-headed, so it's no biggie.
- In Chrysalis Visits The Hague, Lieutenant Fighting Fit is tortured by guilt over hesitating to investigate the disappearance of Junebug and failing to stop a changeling from taking her place and mind-raping her mother. Two years later, he assembles a search party for the real Junebug, obviously trying to make amends for his failures.
- The Immortal Game: In addition to Princess Luna, there's also Twilight Sparkle after her time as Nihilus.
- Pony POV Series:
- There's Fluttershy, after her time as Princess Gaia/Nightmare Whisper, and Fluttercruel, who accidentally turned her into Nightmare Whisper in the first place. They make no effort to make excuses, taking full responsbility for their actions and any punishment they've earned for it. It's made quite clear in their final scene that, although a lot of good did come from their actions, they both still regret their actions and will live with a lot of guilt.
- There's also the redeemed members of the Dark World versions of the Mane Cast, but especially Applejack, who's working hard to atone so that she can join her sister in Pony Heaven.
- Recursive Fanfiction gives Dark World another, rather surprising, example in the Valeyard, the Doctor's evil self and Discord's Starscream. After being killed and sent to Pony Hell, he's tasked with helping the recently departed Pinkie Pie rescue the soul of one of her adopted foals. Along the way, he rediscovers that Good Feels Good and, task completed, he rejects an offer of a lighter sentence in order to help the souls condemned to pull Havoc's chariot find redemption, wondering if he might earn it himself one day.
- The Reading Rainbowverse version of Trixie was very legitimately traumitized by her experience with the Alicorn Amulet and is, apparently, now trying to redeem herself. Somehow.
- In Kitsune no Ken: Fist of the Fox, Naruto is one of these. He was a member of the Kyuushingai ("Nine Terrors"), nine people of mass destruction who caused a lot of chaos across the continent for exactly 365 days; two years after their activities stopped, Naruto is still remorseful about all the bloodshed he helped to cause during that time.
- The Child of Love: Ritsuko tried to atone for helping Gendos schemes. So that she gave Asuka pills meant to undo Gendo's genetic manipulations and turn Asuka's daughter Teri into a normal child.
- A Crown of Stars: After talking with Yui and realizing the weight of his crimes Gendo wants to expiate his sins.
- Ghosts of Evangelion:
- After Third Impact Shinji spends his whole life trying to atone for abandoning Asuka and getting the whole mankind killed.
- Misato strives to atone for effectively abandoning Shinji and Asuka right when they needed her, in spite of her being the only person who cared for them.Misato: It might surprise you to learn I agree with you. Everything you said is true. I did a terrible job with the both of you, and there's no excuse for it. Nothing about the circumstances changes what happened to you. It was criminal, and it was wrong, and I'll regret it until the day I die. But even so, you have to think about your situation here: you aren't equipped to live on your own, and neither is Shinji. You both need a lot of help and support, and there aren't exactly a lot of candidates banging on the door for the job. For better or worse I'm the closest thing to family either of you has.
Asuka: (shaking her head)
Misato: And I do care about you. I can't undo any of the things that have happened to you, but I can do my best to look out for you in the future. And I want to do that.
Asuka: No you don't. The only reason you're bothering at all is because of him.
Misato: That isn't true. But even if it was, does it really matter? Either way —
Asuka: Of course it matters!
Misato: I see. I've really misjudged you, haven't I? All this time, I thought your only interest was in survival. Shinji, me, even Kaji were just means to that end. But it wasn't like that at all, was it? No, of course not. It's so obvious, given what happened with your mom. I guess I never really made the connection because of everything else that was going on.
Misato: Alright then. I think I can understand your feelings now. And I can't really blame you; I'd be pretty skeptical myself if I was in your position. So that means I'll just have to prove it, right? But you'll have to give me the chance to do that, Asuka. I can't force you to accept me. All I can do is do my best to earn you trust. And that starts right now.
- HERZ: Gendo tries to atone for being a bad father with being a good, doting grandfather when he is allowed seeing his granddaughter Akiko.
- Once More with Feeling: Neither Misato nor Hikari understand why Shinji is so determined to and obsessed with making everyone happy. They do not know that Shinji feels inmensely guilty and is trying to make amends because in the original timeline he left Rei alone because she "scared" him, let Misato die because he was wrapped up in his grief, defiled Asuka and abandoned her -which led to her very bloody and gorey death- and wished that everyone died because he thought nobody loved him.
- Scar Tissue:
- After nearly getting Shinji killed Asuka spends the whole fic trying to atone for her behaviour and earn his forgiveness.
- On the other hand, Shinji endured whatever Asuka did to him because he thought that he deserve it after his actions (never helping her when she needed him, leaving her alone after her Mind Rape, masturbating over her comatose body, leaving her alone as she fought for her life before losing and getting quartered and eaten alive, trying to kill her twice ).
- Ritsuko is trying to help both kids and eradicate the Eva technology in order to make up for her actions.
- Shinji and Asuka subvert this in The Second Try, surprisingly. At the beginning it looks like they're trying to save the world after going back to the past because they let it die in the original timeline. However, it becomes more apparent as the story goes on that they've largely come to terms with their failings, and they're not motivated by regret and/or guilt.
- Christian Humber Reloaded: Surprisingly, Vash sometimes is this. He turns himself in, apparently out of regret, after killing his friend Soku and the rest of her family in revenge for her turning him in. After bursting out of the stomach of a rogue dragon, he undergoes a quest to defeat the demon dragon Le Hung Doe. Unfortunately, those aren't even his worst crimes, and he remains largely unrepentant for actions such as killing six million people at the Super Bowl.
- Brave New World by Ri2 has multiple atoners. Father Yamari was actually a homocidal mercenary before dying. He's spent his entire afterlife attempting to atone.
- In RWBY: Scars, Blake's main reason for becoming a huntress is to atone for her years of terrorism and killing by helping others.
- A Study in Regret has Marcel Bernier, the Swiss youth who delivered Professor Moriarty's letter to Sherlock Holmes in "The Final Problem." Marcel was just an Unwitting Pawn, but he still feels some responsibility for Watson's death and Holmes's captivity.
- Another Sherlockian example is Ascended Extra Fred Porlock in the Deliver Us From Evil Series. Porlock turns out to be an English nobleman's son whom Moriarty recruited from university, and, having seen what his employer really does, Porlock begins to slip information to Sherlock Holmes. We also find out that he's one of Inspector Patterson's contacts—Patterson is Scotland Yard's expert on Professor Moriarty.
- The North Remembers: Much of Theon Greyjoy's character arc is spent trying to redeem himself for betraying the Starks by accompanying a band of Wildlings to Winterfell in order to rescue Mance Rayder and kill Ramsay. Later as Stannis lays siege to the Dreadfort, Theon and Asha agree to exchange themselves for Davos, whom Ramsay had captured and taken prisoner, in order to get inside the castle and retrieve the real Lightbringer sword in Ramsay's possession. Once inside, Theon exacts revenge on his former tormentor, only for Ramsay to reveal he had drunken some of Davos' blood, which had been poisoned by an Other blade, and rises as an Other-like being. This finally culminates in Theon killing Ramsay again by using his and Asha's blood to rekindle Lightbringer.
- Forum of Thrones:
- Following the rescue of her little sister, Kersea is no longer forced to work for Clayton and Butterfly. She then decides to make up for her past actions in their service by helping in bringing them down.
- Harpy's actions during the chapter 6 finale, where she risks her own life to get an attempt at killing Maron Mullendore, the real Butterfly are a version of this trope, as she underwent this risk because she was convinced that the situation leading up to it has been entirely her fault for killing the fake Butterfly two chapters ago
- Terroma is revealed to feel heavy guilt over having trained Clayton back in his younger days. After hearing of his former pupil's actions, he decided to return from retirement and to focus on bringing him down.
- In Safe Anchorage Theon Greyjoy sees both his canon rescue of Jeyne Poole and continuing to care for her after his pardon as a way to make up for his canon crimes.
- In Memories Born of Fire, a Star Trek: The Original Series fanfic, Spock stays at Kirk's side after he's poisoned, saying that he has "recently failed to carry out" his duty to ensure his captain's well-being.
- Professor Atani Dukat of Reality Is Fluid is the daughter of Gul Skrain Dukat from Star Trek: Deep Space Nine. It's not a relationship she's particularly proud of, and her opening scene has her formally apologizing for everything the Cardassians and Gul Dukat did to both Bajor and the Federation.
- The Count's World: Count Bleck and his minions in general know they can't completely make up for their actions in Super Paper Mario, but they honestly want to keep trying. Dimentio is this as well on a more personal level.
- Touhou Ibunshu has Yukari, a vicious, cruel manipulator who nearly destroyed Gensokyo in a doomed effort to kill herself. Realizing what a deep pit she's dug for herself, she starts by confessing her misdeeds and repairing the damage brought by the unnatural winter. She's aware it's step one at best and has zero illusions as to how long it's going to take her to actually earn her forgiveness, but the fact she's actually trying makes it clear she no longer wishes for death.
- Several appear in Travels Through Azeroth and Outland.
- In Co-op Mode, due to Gaia's actions, Contessa/Fortuna becomes this.
- In Security, there are quite a few of these, some facilitated by the self-insert protagonist. These include Purity (rebranded as 'Evenstar' of the New York Protectorate), Bonesaw (captured and rehabilitated earlier than in canon), Canary (her power is very useful with crowd control), Lung and Bakuda (pressed into service by the PRT), Emma Barnes (after a traumatic experience with Bakuda and Oni Lee), the Undersiders and Glory Girl.
- The X-Men fic The Wraith Saga presents an alternate timeline in which Jean Grey survived the events of The Dark Phoenix Saga and spends most of the story trying to atone for the destruction that she caused as the Dark Phoenix. At one point, she even returns to the charred ruins of D'Bari, the planet that she destroyed, to contemplate her past sins.