The following have their own pages:
- Jack and Nina from 24. Though all tension is gone from Jack's end and replaced with genuine hatred once Nina kills his wife..
- Jack Bristow and Irina Derevko on Alias. Even though she was a KGB sleeper agent who posed as his wife and constantly walked through the Heel–Face Revolving Door, they clearly wanted to debrief each other quite badly. Complicated by the very real betrayals on Irina's part, not just the original swallow mission, but multiple subsequent betrayals of both her 'husband' and their daughter Sydney. Her attraction to Jack is clear... unfortunately, neither her love for Jack nor her daughter either of them, for that matter could overcome her addiction to Rambaldi's work.
- Alphas: Gary and Anna, though neither of them has any real contempt for each other, and are more close friends than anything else.
- On Angel, Wesley and Lilah Morgan, the head of Wolfram & Hart's Special Projects division, who have a torrid affair throughout Season 4. Angel and the Senior Partners' mouthpiece Eve have a one-night stand in Season 5, although in their case Lorne's Power Incontinence made them do it and they still despise each other afterwards.
- Downplayed in Babylon 5, where Vir Cotto helps Narns escape the Centauri occupation while his ditzy fiancee Lyndisty fondly remembers killing entire villages. Vir was less than thrilled with the setup; and Lyndisty is never heard from again after the single episode in which she appears.
- While they are not the lead characters in Battlestar Galactica, the relationship of Captain Karl "Helo" Agathon and a Cylon copy of Lt. Sharon Valerii is suitably star-crossed. note And despite the attempted gang-rape, demotions in rank, distrust, and Presidential baby-stealing, they are, as of the midpoint of season four, fairly happily married.
- Until Boomer shows up and impersonates Athena... Despite his near-death in the finale, they get a happily ever after.
- Servalan and Avon from Blake's 7. The blatant flirting and occasional bouts of passionate kissing move this one out of the realms of Foe Romance Subtext, but it's still not really a relationship because neither of them trusts the other any further than they could throw a cake underwater.
- In the setting of Buffy the Vampire Slayer, dating the enemy seems commonplace not only for Slayers but their enemies too:
- Buffy/Spike and, to a lesser extent, Buffy/Angel (the latter applies only when Angel actually does something evil, which doesn't happen a lot), though it is lampshaded when Buffy talks of how difficult it is to stake vampires when you're having fuzzy feelings for one.
- The trope is deconstructed when Spike and Buffy get together in Season 6 — the result is a Destructive Romance, due to Buffy's self-loathing over the relationship and Spike's failure to understand Buffy's moral qualms, showing just how potentially harmful one of these relationships could be if enacted in the wrong circumstances. It's worth noting that Buffy doesn't have sex with Spike (at her initiation) until after she realizes that Spike's inhibitor chip no longer works on her and he could kill her.
- Averted near the end, however, as Buffy's influence on Spike fully brings him to the side of good, and thusly Spike is no longer "Catwoman". As such, their relationship enters much healthier places.
- Not just Buffy either. Faith actually does Xander after several prods about whether Buffy has (not to mention she tries to rape him when he doesn't want to have sex with her), and she wants to know what Angel was like. She later tries to get into his pants counting on him going evil because of it (in her words, she intended to stretch out that 'moment of happiness' into a long weekend) before it becomes a strong, non sexual friendship during her Heel–Face Turn. And she teases Spike over what she or Buffy could do to him, then later they discuss sex and it's hinted they did it.
- Most of Xander's love interests turn out to be demons. He even nearly married Anya, who created a universe in which Xander died twice during her first appearance.
- And there was "Wild at Heart", where Oz was into that other werewolf.
- Buffy was actually wooed by Count Dracula himself in "Buffy vs. Dracula". In "The Girl in Question", she even attracted the attention of The Immortal, an Italian Lothario who had racked up quite a hit count in his own right; in this case, however, The Immortal was duped into dating an impostor - or went along with it solely to screw with Angel and Spike. It's ambiguous whether The Immortal is good or bad, though.
- Charmed:
- Phoebe Halliwell and Cole Turner, although initially he was just trying to seduce her so he could kill her. He eventually turned good for a while.
- One episode reveals that the girls' grandmother loved and was loved by a necromancer she fought. The real extent of their relationship wasn't exactly clear, but the entry she wrote on him in the Book of Shadows included his favorite wine and movie, and he was able to exercise some measure of control over her spirit because of their love, so they must have had some sort of relationship.
- Gil Grissom and Lady Heather in CSI.
- Cobra Kai: When Daniel LaRusso's daughter Samantha first dates Cobra Kai student Miguel Diaz in season 1, they have to keep their relationship a secret because Daniel would disapprove of his daughter dating a student from Johnny Lawrence's dojo. They break up after Miguel wrongly suspects Samantha of cheating on him with Johnny's son Robby, leading to Miguel accidentally punching Samantha during an altercation with Robby. Their second attempt at a relationship in season 3, the aftermath of the school rumble in the season 2 finale, goes over much more smoothly, helped by the fact that Miguel and Johnny have cut ties with Cobra Kai to start a new dojo called Eagle Fang. She and Miguel end up convincing the city council to let the All Valley Karate Tournament go on where her father and Johnny were unsuccessful at swaying the council and convince their respective dojos to merge together to take down Cobra Kai. And after fighting off a Cobra Kai assault on the LaRusso residence, they end up being the ones to talk Daniel out of killing Kreese.
- The Company You Keep: Emma, a CIA agent who investigates international criminal activity, has a mutual attraction with very skilled con artist Charlie (neither at first knows of the others' true profession).
- Dark Angel has Max and Logan meet after she steals his priceless Egyptian cat statue. He's the rich-hero-by-night ("Eyes Only") and she ends up helping him solve crime.
- Omen of Dark Oracle, a recurring antagonist, nursed a fairly serious crush on Cally, one of the protagonists, throughout its run. Whether he was just using her initially is up in the air, although by the end he cared enough to take a bullet for her.
- Dexter:
- Dexter Morgan
- Dexter and Lila in season 2. It says something when Dexter is a serial killer and the girl he dates is darker than him. Her psycho side only really comes out after Dexter breaks up with her, and she becomes a Yandere towards him.
- Dexter and Hanna McKay in season 7. In this case, he knew that she was a killer right from the jump, and in fact considered adding her to his kill list.
- Dexter Morgan
- Doctor Who:
- By series 6 the Doctor became romantically involved with a convicted murderer and psychopath raised to assassinate him. She succeeds more than once, but he keeps coming back for more. (Averted, though, in that very early on in their relationship (from her perspective) she changes allegiances completely, and her loyalty is absolutely and without question with the Doctor from there on out.)
- Subverted with the Mistress, a female incarnation of the Master, who is disgusted when Clara suggested that there might be a romantic relationship between her and the Doctor. She is adamant that it is friendship, not love.Clara: Must be love.
The Mistress: Oh don’t be disgusting. We’re Time Lords, not animals. Try, nano-brain, to rise above the reproductive frenzy of your noisy little food chain, and contemplate friendship. A friendship older than your civilization. And infinitely more complex.
- Pops up in Dollhouse with the brief interaction between Bennett Halverson and Topher Brink. Both of them are hammered hard by their various Geeky Turn Ons even before they meet each other (Topher considers Bennett a supreme genius, and Bennett has a massive crush on Topher) and there's several adorable moments between them, including one where Topher ends up implying to Bennett without saying anything that he thinks she's beautiful and has a priceless embarrassed reaction. In fact, Topher says she would have been perfect, except for the fact that she's insane and wants to brutally torture and murder Echo for leaving her to die. Kinda kills the relationship...
- And yet somehow, they're back to flirting in her next appearance, until something even more drastic comes to kill their relationship.
- Mountie Fraser's doomed love affair with bank robber Victoria in Due South is a deconstruction. Turns out, it's really hard to have a healthy relationship with a bank robber and murderer, especially if she has any hard feelings over you putting her in prison after falling in love.
- Sherlock and Irene Adler, who is actually Moriarty, on Elementary. She seduced Sherlock into a relationship in order to figure him out and why he kept foiling her criminal plans, but did eventually develop real feelings for him. Once she got what she wanted, Moriarty then fakes "Irene"'s death so that she can be free to pursue her plans without Sherlock's interference.
- For all the animosity between them, Firefly's Mal and Saffron do manage to show a teensy, tiny bit of affection toward one another - when they aren't Pistol-Whipping each other or leaving the other party naked to die in the middle of a desert. And don't forget, they technically are married. Only if you don't count her flagrant bigamy — who hasn't she married?
- General and I: Bai Ping Ting and Chu Bei Jie are on opposite sides of a war, and frequently fighting against each other. This doesn't stop them from falling in love and getting married.
- Get Smart: The scene between the Chief and KAOS agent Mary Jack Armstrong in "Survival of the Fattest" reveals they had this relationship back when he was an agent, though they're now Amicable Exes.
- Good Omens (2019): A platonic example until season 2.
- Despite formally belonging to the opposite sides, demon Crowley and angel Aziraphale have been involved with each other for more than 6000 years. At the end of season 2 it is revealed that they are in fact in romantic love.
- Also, surprisingly, season 2 revealed a secret romantic relationship between the supreme archangel Gabriel and the prince of Hell Beelzebub.
- In Season 2 of Gotham, 12-year-old Bruce Wayne has this going on with two girls: Selina Kyle, who works for the Gotham Mob, and Silver St. Cloud, who is trying to seduce Bruce on her uncle Theo's behalf; Theo wants to murder Bruce.
- In Grimm Nick (a Grimm) and Adalind (a Hexenbiest) start a relationship which is kind of taboo for their respective kinds. Adalind does make a Heel–Face Turn eventually.
- Hannibal has Hannibal Lecter's intense feelings for protagonist Will Graham, feelings that start with lighthearted curiosity that evolve into an all-consuming love so powerful he'd rather get arrested and go to prison for three years rather than live a free life without Will. Will, on the other hand, feels that same intense feeling for Hannibal but is convinced it's feelings of friendship from their pure understanding of each other until he's flat out told otherwise. He eventually comes around, breaking Hannibal out of prison, joining him in the pack killing of Francis Dolerhyde, and accepting Hannibal's romantic affections... before throwing them both off a cliff. It's a complicated foemance, to say the least.
- Kono's mystery boyfriend on Hawaii Five-0 has turned out to be Adam Noshimura, the heir to Honolulu's yakuza clan. Admittedly he's trying to turn their operations legit, but he's not finished yet.
- Heroes: Mohinder and Eden, Sylar and Elle (at least at first), Matt and Daphne, Lydia and Samuel; it goes on forever, thanks to the show's Heel–Face Revolving Door.
- Intergalactic: Ash ends up getting involved with Verona, an unrepentant thief whom she sent to prison after they become Fire-Forged Friends in dire circumstances and discover a mutual attraction.
- Killing Eve: Villanelle's intense Villainous Crush on Eve, the MI5 agent hunting her, is eventually revealed to be reciprocated. Eve has no idea what to do about it, since Villanelle is a violent Serial Killer who brings out her own dark side. On the othr hand, whatever good is in Villanelle gradually begins to show itself for Eve; meeting her is what allows her, a self-described psychopath, to undergo Character Development and show some hints of humanity. Season Two ends with Villanelle trying to convince Eve to run away with her, and shooting her when she refuses. Season Three, on the other hand, ends with Villanelle promising to walk out of her life forever and leave her alone if that's what she wants, but it's clear that Eve can't truly let her go.
- Nate and Sophie's pre-series relationship on Leverage...even though he remained faithful to his wife and she believes he was never really tempted.
- Xev and Prince, Lexx.Prince: Do you still feel anything for me?
Xev: A little.
Prince: You shouldn't. - Jack and Juliet from Lost. They started to develop feelings for each other before Juliet's Heel–Face Turn. Then later, in the 1970s time travel sequence, Sawyer and Juliet. Although, by this time Juliet is a full Face, and Sawyer's intentions are always questionable. You could also argue Kate and Sawyer considering Sawyer's Heel–Face Revolving Door.
- In The Man from U.N.C.L.E., Napoleon Solo apparently has an ongoing flirtation with Angelique, an agent of THRUSH.
- In NCIS Ziva had a relationship with a crooked, alcoholic Mossad agent. It failed, spectacularly.
- Nikita. Michael and Nikita are on opposite sides but used to work together. Sometimes it's subtext - their inability to kill each other - but sometimes not so much. By the end of the first season, Michael's switched sides, so this trope no longer applies and they revert to being a Battle Couple.
- Paris Police 1900: In a very twisted way, the Prefect of Police, M. Lepine, for his wife by the end of the first season. It was implied that they had never had a particularly passionate relationship... until she tried to kill a corrupt cop who'd arranged for very nasty things to happen to her in order to discredit the boss, and got away with it. The final scene has them in bed about to go at it vigorously, and M. Lepine saying that he's never slept with a murderess before.
- Party Animals: Ashika, a Tory MP candidate, and Scott, a lobbyist turned campaign manager for her Labour opponent. After a lot of UST, they do fall in love and sleep together but at the end of the series she's convinced, wrongly but with good reason, that he's leaked the photos that cost her the seat.
- In Power, Angela Valdes is a federal prosecutor assigned to a task force to bring down a major cartel boss by catching and flipping his mysterious and anonymous New York distributor. Meanwhile, she's having an affair with her high school sweetheart James St. Patrick, who, unbeknownst to her, is the very distributor she's chasing.
- Power Rangers:
- Power Rangers in Space: Zhane the Silver Ranger with Astronema. Yes, the main antagonist. The romance lasts just one episode, spoiled by another battle. Later on after the Luke, I Am Your Sister reveal, Andros the Red Ranger invokes My Sister Is Off-Limits retroactively.
- Power Rangers Time Force has another one-episode version: Lucas the Blue Ranger is a ladies' man, and Nadira falls for him after she discovers some love poetry he's written. This is unfortunately one-sided, as she's Daddy's Little Villain and said Daddy Ransik is an overprotective dad; after Ransik puts Lucas through some Twerp Sweating he panics and starts going "Please Dump Me!" By the way, that poetry that Lucas wrote was actually for his car. They do seem to get together post-season, though, once Nadira and Ransik have both made Heel Face Turns.
- In Power Rangers Ninja Storm Dustin with Marah, but she ends up betraying him after considering a Heel–Face Turn. When she and her sister bail on Lothor for real at the end of the series, she's quick to ask Cam if Dustin still has a crush on her. Cam says they can talk about it once they're out of the exploding spaceship.
- There are shades of this in Power Rangers: Dino Thunder, with Tommy sharing an attraction with Principal Randall... who is really Elsa in disguise.
- Helen Magnus and John Druitt of Sanctuary. They were engaged until Druitt acquired an Enemy Within and became Jack the Ripper. Now he alternates between helping and tormenting Magnus, but admits he still loves her. It is implied in a few episodes that she was once in love with him and those feelings as well as their tumultuous past has continued to haunt her emotionally. However, his betrayal hurt her deeply and makes her unable to ever truly forgive him.
- Scandal: The beginning of Quinn's romantic relationship with Gideon, a cub reporter who seems on the verge of breaking the Amanda Tanner story. An especially tragic end, as Gideon dies and Quinn is effectively framed for the murder.
- In Stargate SG-1, Daniel Jackson met Vala Mal Doran when she attempted to steal the Earth ship Prometheus. An undeniable attraction began soon after. In at least one timeline, they eventually got together before falling victim to a literal Reset Button.
- In a Farscape connection; Aeryn Sun (also played by Claudia Black) tried to kill John Crichton (played by Ben Browder who'd go on to SG-1 as well, where the fact that he and Jackson's actor Michael Shanks resemble each other was brought up a few times). They worked out their issues and eventually married and had a child.
- Star Trek:
- Captain Picard and archaeologist/thief Vash in Star Trek: The Next Generation. Also, Captain Sisko and Kasidy Yates in Star Trek: Deep Space Nine (although the fact that Kasidy was a smuggler doing business with The Maquis was as swiftly ignored as it was tacked on). There's also Odo and the Female Changeling from Deep Space Nine.
- Weird example: in the Star Trek: Deep Space Nine episode "Our Man Bashir", Bashir's character in a holodeck scenario, a James Bond expy, is in a relationship with a female KGB agent.
- Supernatural:
- Sam Winchester (a hunter of supernatural monsters) and Ruby (a demon). She eventually seduces him while mentoring him to kill other demons, and they start a physical relationship. In a later episode, their foreplay jumps straight into Hemo Erotic territory when she lets him drink her blood, to which he is addicted. When he admits it to Dean, his brother is more than squicked out.
- Castiel and Meg share a lot of sexual tension before they make out, and later express their love for each other. An angel and a demon, how poetic.
- Teen Wolf: Scott and Allison. A variation in which he knows she's on the opposing side, or, that her father is anyway- Also, starting season 3, Danny and Alpha Twin Ethan in a homosexual and supporting character version of this.
- John Connor and Cameron in Terminator: The Sarah Connor Chronicles. He's the future savior of mankind, destined to save humanity from a race of machines. She is part of that race of machines, and originally programmed to assassinate him. Though reprogrammed to be one of the good guys, it doesn't always stick... Sexual tension ensues. And how.
- Emma and Olly from The Thick of It. Well. He's working for the Secretary of State for Social Affairs and Citizenship, she's working for the shadow Dosac secretary. But then their bosses know about their relationship and his at least actively encourages it -just so Olly can leak policies to Emma, or know of hers. It also works the other way round. However, it's not clear that they actually even like each other...
- Damon and Elena from The Vampire Diaries. Both in the series, and the books.
- In Vegas there's a definite attraction between Jack Lamb and Mia Rizzo from about the second episode, and the two end up in bed at the Christmas Episode and secretly dating after. The one is the younger brother of Sheriff Ralph Lamb and his right-hand both on the ranch and in the squad room, and the other is a senior finances manager at a mob-run casino and the daughter of a made man.
- CJ and Danny from The West Wing are a mild version of this: she is the White House press secretary, he is the chief White House correspondent from The Washington Post. Her loyalty is completely with the president and protecting him from his political enemies, and he refuses to neglect his duty to report accurately and to inform the public of as much as he can find out, two sets of interests which of course come into conflict quite frequently. They mainly have an up-and-down cycle of trying to date, pissing each other off, giving each other the cold shoulder, trying to date again, breaking up because of ethics worries, being unable to resist each other, deceiving each other again, and fighting over it, ad infinitum. These two get a rare happy ending, as CJ quits politics despite an offer from President-elect Santos to go run a much-less-controversial charity initiative, and mentions that Danny is waiting for her at LAX "with a tub of sunscreen". A flash-forward at the beginning of season 7 shows them happily married with a baby on the way.
