History MoralityChain / AnimeAndManga

* In ''Literature/ThatTimeIGotReincarnatedAsASlime'', Rimuru is the reason a lot of very powerful monsters haven't gone on rampages throughout the world. [[spoiler:According to Chloe, in the timelines where he dies fighting the Eastern Empire, it sends both his best friends, Milim and Veldora, on a world-destroying RoaringRampageofRevenge]]. Rimuru is also the master of [[spoiler:four primordial demons, which are the strongest and most ancient demons of that world]]. [[Elmesia warns him not to die because he's the only person in the world that can keep those demons in check]].

* In ''Manga/BlackLagoon,'' Rock acts as a morality chain for Revy that moves her from NeutralEvil to SociopathicHero, willing to help Rock pull off good endings in the ''Yakuza'' and ''El Baile de la Muerte'' arcs (failure and partial success respectively). Suffice it to say that in the event of Rock's death, Revy would make the events of the ''Nazi'' arc look like cheerful shoujo by comparison.

* In ''Manga/HellTeacherNube'', the students of class 5-3 become [[NobleDemon Minki's]] Morality Chain altogether unwittingly -- she believes she's still a nasty evil [[{{Obake}} Oni]] who [[ChaoticEvil doesn't disregard human life as much as enjoy extinguishing it]]... until she sees Hiroshi, Kyoko, and Miki in danger, leading her to [[TakingTheBullet shielding them with her own body]]. Similarly, her big brother, Baki, gleefully shifts from LaughablyEvil to NeutralEvil [[AttentionDeficitOohShiny depending on his whims]], but will go ''[[BerserkButton insane with fury]]'' if [[KnightTemplarBigBrother anyone hurts his beloved sister]]. Therefore, when she [[HeelFaceTurn decides to fight him to protect her friends]], and he sees [[PapaWolf Nube]] give HIS life to protect Minki, Baki immediately [[HeelFaceTurn allies himself with Nube]] on the condition that he should never hurt Minki.

** In some ways, Fisher Tiger was this to [[spoiler: Arlong and some of the other crew.]]
** Koala could be argued to be this for Tiger since her innocence convinced him that there was a hope for positive relations between Fishmen and humans, an ideal that he finally believed [[spoiler: on his death bed.]]

*** Both parents of [[spoiler: Donquixote Rosinante]] are an InvertedTrope. [[spoiler: Rosinante]] went through the same DarkAndTroubledPast as [[spoiler: his brother Doflamingo]], but the deaths of his gentle parents instead inspired him [[TheMole to work against his brother]] and keep their memories alive [[spoiler: Rosinante]] himself is a [[SubvertedTrope subversion]] for [[spoiler: Doflamingo]], in that he doesn't explicitly try, or can't, stop [[spoiler: Doflamingo]] committing horrific acts and [[spoiler: Doflamingo]] has no issue murdering him when his true identity is revealed.

** The DarkAndTroubledPast of [[spoiler: Doquixote Doflamingo]] shows that pretty much the only person he showed genuine love to [[MommasBoy was his mother.]] [[spoiler: After she died of illness, he blamed his father for her demise [[PatriCide and killed him]].]]

* PlayedForHorror in ''Manga/MariaNoDanzai'': Maria [[BestServedCold has spent the last two years]] preparing to [[KnightTemplarParent avenge her son Kiritaka by murdering the bullies responsible for his death]], and is prepared to do whatever it takes to kill them all. However, after [[AlphaBitch Shikimi]] sends Iijima to beat up Maria [[DisproportionateRetribution for taunting her at school]], Maria quickly realizes that, once she kills Shikimi, Iijima could be used by the police or even by [[BigBad Okaya's]] gang to draw a connection between the two, potentially outing her as Shikimi's murderer. Maria prepares to [[HeKnowsTooMuch silence Iijima by killing him]] when the two go to a love hotel, but then [[ISeeDeadPeople an apparition of Kiritaka]] reminds her that Iijima is not one of her targets. Shocked at what she was about to do, Maria relents and [[EveryoneHasStandards agrees that Iijima doesn't need to die]], and decides to silence him by other means after killing Shikimi. What makes this horrifying, though, is that Kiritaka's "ghost" has a hole where his face should be, ''[[BodyHorror leaving his brain and blood-stained tongue to spill]]''. Clearly Maria is still traumatized from cradling his mangled remains.

* A variant of this appears in ''Franchise/{{Devilman}}'', wherein Akira reasons after humanity turns on itself that only Miki Makimura and the love he has for her makes him stay human and have hope for humanity... what makes this all the more heart wrenching is that by the time he says this, Miki has already been killed off by a paranoid mob. When he arrives to find the psychopaths parading her head and dismembered body around on pikes, he is enraged to the point that he completely incinerates the crowd while bellowing inconsolably. When Akira finally returns to his senses, he cradles Miki’s head in his arms and laments the loss of all hope, turning his back on humanity entirely and resolving to fight only for the other Devilmen against Satan and his army of demons.
** In ''Amon: The Darkside of the Devilman'', the fallout of this trauma goes even further, as it unseats Akira's control over Amon, eventually allowing the demon warrior to reverse control entirely and briefly [[GrandTheftMe seal Akira away]].
** A much lighter version of this exists in the original 1972 Anime; Devilman/Akira still loves Miki very much and sees her family both as his friends and allies, but knows that he can't reveal that he's a host to one of the Demon Tribe's strongest warriors to Miki and her family, or they may be terrified of him; ultimately this turns out not to be the case in the series finale, but Miki is still what prevents Akira from transforming with no regard for anyone nearby.

* ''Anime/CodeGeass'': Euphemia is this for Suzaku. [[spoiler:After she dies, he sells out his best friend Lelouch in exchange for a promotion, eschewing his ThouShaltNotKill philosophy for cold pragmatism, then eventually agreeing to use a FantasticNuke in a battle that destroys half of Tokyo.]] Ostensibly though, it could be seen as Euphemia finally GIVING him a sense of a Moral direction considering how he sold out his home as he beleived it was wrong for an oppressed people who want their own freedom. Even his original goal (Become the Knight of One to rule over japan as his personal territory)reflects this as he didn't ever seem to care what the people wanted; only what would stop them complaining.
** Lelouch on his own has several between Nunnally, Kallen, Shirley and Euphemia; the issue is he's more willing to push morality to the side if he's certain the amoral things he does will result in a net good and he'll accept the consequences, sin and condemnation if he's wrong. It's only when those chains start breaking does his own Sanity slippage start, he pushes those who connected to them away [[spoiler:if they're even still alive to break them]] and commit to doing the wrong thing regardless of what it will do to himself.

** The Lovelace family is this to Roberta. Her RoaringRampageOfRevenge in ''El Baile de la Muerte'' started when [[spoiler:Garcia's father, the leader of the Lovelaces, was blown to smithereens.]]
* [[CheerfulChild Yachiru]] from ''Manga/{{Bleach}}'' is this to [[AxCrazy Kenpachi]], to an extent, even though she can be just as violent as him at times. Kenpachi may be a savage now, but before he took in Yachiru he was little more than an animal with a sword. ''All'' he did was kill; he didn't even care that he had no name. He may be on the bottom of the morality ladder now, but before meeting her, ''he wasn't even aware it existed.''

** Early on, Karino makes it clear that Touma is the only person who she cares about and doesn't care if she hurts anyone else... [[SubvertedTrope but ends up becoming friends]] with one of Touma's school buddies after he cooks her a meal.