People turning evil out of love in literature.
- Agatha Christie loved this trope. Many of her characters' motivations for murder came out of love for their significant other. Notable examples include:
- Vera Claythorne from And Then There Were None (although she wasn't the murderer, her motivation for her crime, allowing a child in her care to swim out to sea and drown, was for her lover, who also happened to be the child's uncle, to inherit his estate),
- In Nemesis, the girl whose murder instigates the plot is said to have died because of "love, [...] one of the most frightening words there is in the world." Her adoptive mother, rather than give her up so she could marry a delinquent, gave her an overdose of sleeping medicine, secretly buried her in the garden, then strangled and bashed another girl's face in so everyone would think the delinquent had killed her.
- Also the killer's motive in the Hercule Poirot novel Three Act Tragedy. The murderer wants to marry their crush, but is unable to do so without committing bigamy, as he's already married and is unable to divorce his wife due to her being in an insane asylum. Not many people are aware of this fact, but to prevent the possibility of a scandal arising, he murders the only person who knows about his first marriage — his childhood friend.
- Scrooge's greed in A Christmas Carol ultimately stems from his desire to marry and provide for his impoverished childhood sweetheart, who has no dowry. Unfortunately, the turn his personality takes in scrabbling to be wealthy kills Belle's love for him.
- Definitely the case for Vlad Dracula and Elizabeth Bathory in Count and Countess. To get to Elizabeth's time period, Vlad has to find a way to outlive his natural lifespan. For that cause, he will do anything. Even if it turns his entire nation against him.
- A Court of Thorns and Roses: Tamlin's love for Feyre leads him to collaborate with the King of Hybern when she leaves him in order to live in the Night Court.
- Philip Cutler from the Cutler Series by V. C. Andrews originally dated the heroine Dawn in the first book. But even when it's revealed that Dawn is in fact Philip's sister/half-sister/aunt and she loses all romantic interest in him, Philip's original interest becomes exceedingly twisted and he still lusts after her regardless of their blood relation and eventually rapes her. He holds onto his obsession well into adulthood and eventually marries a woman he attempts to mold into Dawn's image. When Dawn dies in Midnight Whispers Philip transfers his obsession to her daughter Christie.
- In The Dark Descent of Elizabeth Frankenstein, Victor starts his experiments after he almost loses Elizabeth to illness. However, it becomes this trope once he orchestrates Justine's death because of his jealousy over their friendship, and when he mutilates Henry and leaves him for dead once he confesses his feelings for Elizabeth.
- Kirsten in Deltora Quest 3: Shadowgate. She fell in love with Bede, a Masked One, who seems to reciprocate.. .but he fell for her sister instead. Her response involved yandere-like jealousy, using dark magic to enslave Bede to her, transforming her sister into a pendant to control him and turning him into a decoy guardian to confuse anyone seeking to destroy the Sister of the North.
- The Divine Comedy:
- Francesca of the Circle of Lust blames her adultery on love, a force so strong that it left her and her brother-in-law with no agency in their sin. Her romantic language is so beautiful that Dante faints from distress, but every discussion of love outside of this sinner's excuses makes it clear that love is an intelligent will to do good for others, as opposed to Francesca's view that love is really wanting to have sex.
- Virgil explains in Purgatory that love can lead to evil only because love is the cause of every single human behavior. Lust, gluttony, and greed are caused by excessive love for physical pleasures, sloth is caused by love that is not acted upon, while wrath, envy, and pride are love for the suffering of others.
- Doctrine of Labyrinths: The Mirador has a Show Within a Show example: Mehitabel stars in a play where the villain commits multiple murders to win the heroine's love and tries to justify it by telling her it was "all for you".
- The Dresden Files: Discussed in Changes, when Harry agrees to serve Queen Mab in exchange for the power to save a loved one. Different characters have different opinions on whether love can lead a person to damnation or save them from it. The narrative suggests that both opinions have their merits, but inclines towards the latter.Uriel: Everything else flows from there... Whatever you do, do it for love. If you keep to that, your path will never wander so far from the light that you can never return.
Mab: So many terrible things are done for love. For love will men mutilate themselves and murder rivals. For love will even a peaceful man go to war. For love, man will destroy himself, and that right willingly. - One of the major themes in KJ Parker's Engineer Trilogy. After being condemned to death by the Mezentine Empire, Ziani Vaatzes kills three people with his own hands, escapes to a technologically backward country and directly causes the deaths of over seventeen thousand Mezentine soldiers by overseeing an advanced weaponry program, all the while intending to betray the people he's selling the weapons to, because, in his own words, "I'm in love with my wife, you see. If I die, I'll never see her again. So I had to live. It's that simple." It's made all the worse by the fact that Vaatzes knows exactly what the consequences of his actions are going to be and plans them meticulously in advance...but never thinks of himself as having a choice in the matter, because love is making him do it.
- Great Expectations: When Miss Havisham falls in love with Compeyson, who takes her money and then leaves her (he was a swindler and a thief), she decides to use her beautiful adopted daughter Estella to wreak vengeance on men. She eventually sees the error of her ways, which leads to an My God, What Have I Done? moment before she meets her end.
- Used straight in Harry Potter...sort of. J. K. Rowling has said that she thinks of Dumbledore's youthful flirtation with world conquest and Muggle subjugation as the result of his blinding, infatuated love for Dark-Wizard-in-the-making Gellert Grindelwald. Of course, this doesn't acknowledge that the past!Dumbledore we saw in Deathly Hallows was exactly the kind of Machiavellian bastard with a thing for controlling people who would be drawn to that kind of ideology himself. (And if that weren't enough, he's got a tragic backstory involving Muggles attacking his sister for being a witch, an act which effectively destroyed his family and left him understandably bitter.) Dumbledore himself acknowledges his character flaws, which is why he's never sought Ministry offices (the reason for which is something that Harry never quite understands). It's possible that Dumbledore had a crush on Grindelwald that caused them to spend time together, and that he influenced Dumbledore into becoming the Muggle-hating bastard he was until his Cynicism Catalyst prompted his Heel–Face Turn. Inverted with the Big Bad of the series, Lord Voldemort. A running theme in the books is that his evil stems in part from the fact that he can't understand love.
- Cypher/Mao Fanchu/Wu Zhang's motivation in the H.I.V.E. Series is stopping Overlord because of the murder of his wife. He even goes to the lengths of attempting to kill thousands of HIVE students.
- "Kissin' Kate Barlow" from Holes, driven by grief over the loss of the man she loved, becomes an infamous outlaw. Her first targets are the racists who murdered her beloved. Previously, she was innocent Katherine Barlow who made delicious peach preserves and taught schoolchildren.
- Victor Hugo:
- Eponine in the 1862 novel Les Misérables provided a relatively mild example of this: in love with Marius, the quite literal boy next door, and aware that he was besotted with Cosette, Eponine disguised herself as a boy and lured Marius to the barricade, intending for them to die together. She eventually took a bullet intended for him and died giving him Cosette's letter, though to this day her motives are debated. Considering that Hugo's own daughter Adele became utterly obsessed with a soldier, running away, printing fake marriage announcements, and even trying to drag him to a hypnotist so that he'd marry her, she may have inspired some Truth in Literature on the part of her father.
- In The Hunchback of Notre Dame, it is only once Claude Frollo falls in lust/love with Esmeralda that the nastier sides of his personality come out. Nearly every instance of death and disaster in the book occurs as a direct result of his obsession.
- C. S. Lewis believed that, without divine grace, human love is ultimately selfish and eventually destroys the object of its affection. In other words, Divine Love Redeems, but Human Love Makes You Evil. This plays out in a few of his novels:
- In Till We Have Faces, Orual's love for her sister Istra leads her to unintentionally cause Istra to be exiled. At the end of the novel, Orual realizes to her horror how much of her "love" was actually jealousy of her sister and the gods. Istra and the gods forgive her.
- In The Great Divorce, it's not uncommon to hear damned souls demanding that those they love in Heaven accompany them back to Hell. What makes it worse is that, in this story, there is nothing — besides their own Pride — preventing the damned from being redeemed and entering Heaven themselves. This, however, is not love, as the main character makes clear:Excess of love did ye say? There was no excess, there was defect. She loved her son too little, not too much. If she had loved him more there'd be no difficulty. I do not know how her affair will end. But it may well be that at this moment she's demanding to have him down with her in Hell. That kind is sometimes perfectly ready to plunge the soul they say they love in endless misery if only they can still in some fashion possess it.
- In The Four Loves, discussing three out of four of the loves goes into how they go evil.
- The Lightlark Saga:
- An enforced example; Wildlings are cursed to murder the person they fall in love with and it's indicated the curse compells them do so. Isla's mother attempted to resist the curse to spare Isla's father, only for him to end up killing her shortly after their daughter's birth (he then took his own life). Or so Isla was led to believe.
- It's revealed the whole reason the curses were cast is because Aurora was so devastated and bitter that her fiance left her for her best friend, she tried to curse them using the Heart of Lightlark but accidentally cursed everyone in the process.
- Mortal Engines: Hester Shaw in Predator's Gold. She sells Anchorage's location to the Huntsmen of Arkangel, out of jealousy for Freya, who she thinks is trying to steal Tom from her.
- Paradise Lost: Adam's fall, and thus the fall of all mankind, comes about as a result of his absolute adoration for Eve, who he can't bear to live in Paradise without. As soon as he falls for her, Adam blames Eve for his own decision and he insults her until she bursts into tears.
- The Reynard Cycle: Reynard's dogged pursuit of the Countess Persephone leads him to sacrifice the lives of several of his companions and murder enemies both real and imagined. When it all turns out to be for naught, things take a turn for the worse.
- The Rifter: A "Grief Makes You Evil" variant. When Ravishan died, John sank all of northern Basawar in the sea. But then he pulled himself together and began to rebuild the world. Laurie, however, mourning for her husband and child and ruined life, became a true monster, and never recovered. Love on the other hand is a great force for good.
- K.J Parker's The Scavenger Trilogy: Several characters cause great harm under the influence. Ciartan's obsession with Xipho leads him to kill her unborn child. His love of Xipho and his schoolmates leads to his pivotal betrayal of Tazenticus. Lysalis seems hollowed out by it, and is capable of doing anything in its name, as would her father.
- Skulduggery Pleasant: Caelan justifies his murder sprees as this, claiming that the women he stalked and obsessed over seduced him, broke his heart and drove him to violently murder them, it was even his Motive Rant while he was choking Valkyrie, but it's very likely that his "reasons" mostly exist in his head, and he's truly just a severely screwed up individual.
- In Juliet Marillier's Son of the Shadows, the heroine's rejection of a suitor makes him more and more evil, culminating in several attempts to kill her lover, among other things.
- One of the main themes of A Song of Ice and Fire is that love isn't much of a motivation for good. Jaime Lannister, Petyr "Littlefinger" Baelish, Lysa Arryn all did some pretty awful things which they claim was motivated by love. It's also at the root of the original civil war against the Targaryens.
- As soon as Jaime's near-worship of Cersei begins to wane, his Heel–Face Turn begins.
- It's difficult to get a solid reading on the motives of Petyr "Littlefinger" Baelish because of all the effort to which he goes to conceal his motives from rival players of the game of thrones, but the going interpretation from what little he's let slip is that he single-handedly instigated a massive civil war, resulting in the suffering and death of millions, just so he could get the husband of his childhood sweetheart disinherited, banished, and (most importantly) get their marriage invalidated. He could then pick her up on the rebound after having gathered enough power and wealth on the side to make a socially acceptable marriage proposal to a Noblewoman of her status. Or, in short, Murder the Hypotenuse turned up to eleven. It doesn't end very well for him though, as she also gets killed during the war. He then chooses her daughter instead.
- Surprisingly, Tywin Lannister may be a partial example (more like Loves Makes You Eviller). He was never a nice guy, but it seems that his wife's death was a Despair Event Horizon which diminished his ability to care even for his children.
- Star Trek Expanded Universe novel Reunion (featuring characters from the later Star Trek: Stargazer series, although taking place later in the timeline) involves an assassin attempting to kill several characters, while framing Idun Asmund (who was raised by Klingons) of the crimes. In the end, it is revealed that the culprit is Dr. Carter Greyhorse, who blames the characters for the death (accidental) of Gerda Asmund, Idun's twin sister, with whom he was in a secret relationship for 18 years.
- Star Wars Legends:
- The Legacy of the Force novels have Jacen Solo going dark for similar reasons to Anakin's. In one novel he flat-out admits he's doing exactly what his grandfather did, but he's confident he can do it right. The irony being, he sort-of unites the galaxy in the end, so he wins after all.
- Jolee Bindo from Knights Of The Old Republic puts it best:"Love doesn't lead to the dark side. Passion can lead to rage and fear, and can be controlled, but passion is not the same thing as love. Controlling your passions while being in love, that's what they should teach you to beware, but love itself will save you, not condemn you."
- Tolkien's Legendarium:
- The Fall of Gondolin: Maeglin of Gondolin lusts after his cousin, Idril. Since he can't have her, Maeglin ends up willingly betraying Gondolin's position to Morgoth.
- The Silmarillion: Celegorm's (implied) planned rape of Lúthien was explained by "love" in the book, although it is debatable whether one may call that "love". "Lust" seems more appropriate.
- Beren and Lúthien:
- Gorlim reveals to Sauron the hiding place of Barahir, the leader of the rebels of Dorthonion, to be reunited with his wife Eilinel.
- Daeron's love for Lúthien leads him to betray Beren to Thingol, who most definitely intended to kill the guy, and later to get Lúthien in trouble for trying to follow Beren.
- Tortall Universe: Mastiff, book 3 of the Beka Cooper trilogy, has Tunstall, who joined the dark side in a misguided attempt to secure a future with the woman he loved, Sabine of Macayhill.
- Trapped on Draconica: Gothon became evil because he was so desperate to save his sick wife that he resorted to dark power. Does this sound familiar?
- Opaline turns her back on The Ultra Violets after she sees Cheri kissing Albert Feinstein, Opal's crush. It really was the other way around, but she won't hear any of it.
- The White Queen in The Unexplored Summon://Blood-Sign became evil because of her love for the main character Kyousuke. Initially, she was childishly innocent, to the point of easily making a promise to never hurt anyone, if it meant she could stay with him. However, others coveted her immense power. A number of people pretended to be Kyousuke, which started a chain of events that led to countless deaths. The real Kyousuke was horrified and tried to flee, with the Queen in pursuit. Eventually, he threw himself at her, trying to stop anyone else from dying, but she didn't kill him like he expected. He resolved to never give up until the Queen was destroyed, while the Queen similarly resolved to never give up until they were together again. Then an army approached, intending to kill the Queen. To avoid Kyousuke being killed in the crossfire, the Queen had no choice but to break her promise further and slaughter them all.
- Tasha Ozera from Vampire Academy, frames Rose for Tatiana's death so she can have Dimitri.
- In The War of the Flowers, Eamon Dowd's Face–Heel Turn begins with his love for a fairy. This trope is explicitly pointed out during Dowd's Motive Rant directed at the main character, Theo. He claims that he's nothing like Lord Hellebore because while they both did terrible things, Dowd did them all for love. Theo responds that that's the most terrifying thing he's ever heard.
- Warrior Cats:
- Ashfur. After his former Love Interest Squirrelflight rejects him, he attempts to murder her father and frame her mate for it, and later, he tries to murder her children by blocking their escape from a raging fire. All so that she could feel the pain he had when she rejected him. He is murdered not long afterward by one of the cats he'd tried to kill. When Jayfeather (another one of the cats he'd tried to kill) sees him in the feline equivalent of heaven, he asks his Spirit Advisor Yellowfang why Ashfur is there instead of in the Dark Forest, where murderers/traitors usually go. Yellowfang's response: "His only crime was to love too much."
- Mapleshade. She loved a cat from another Clan (which is forbidden), Appledusk, and became pregnant with his kits. Her Clan assumed that the father was a warrior who'd recently been killed in battle (by Appledusk, no less.) When the truth came out, ThunderClan banished her and the kits, and she tried to join her mate in RiverClan. The kits died when trying to cross the flooded river. Appledusk blamed her for their deaths, and also revealed that he no longer cared for her; he'd taken a new mate within his own Clan. She then, in her rage and grief, saw a vision of her three kits and became convinced that they were not at peace, so she murdered the cat that revealed the secret, then the cat who'd first assumed that the father was the deceased warrior, and then Appledusk himself. (She was killed by Appledusk's apprentice and went to the Dark Forest.)
- This could be a subtitle of Wuthering Heights, although it would tie with Love Makes You Crazy. This obsessive, unhealthy love and infatuation between Catherine Earnshaw-Linton and Heathcliff contrasts with the later romance between Catherine Linton and Hareton Earnshaw.
