Wherein two characters interact and work together, and are designed to emphasize each other's positive qualities. Similar to a Morality Pet, except the boost is directed to the character's cuteness rather than their morals.
This can mirror, but not usually replicate, what could be a romantic pairing. Actual romantic stories tend to involve a lot of drama and seeing characters at their weakest and most awkward, occasionally becoming Plot Tumors if they become the sole definition of any given character. Sufficiently cynical fans are always wary of Character Derailment and Shipping Bed Death, while other fans are just very possessive of their beloved characters; they do not even want the potential to reach the Die for Our Ship stage. The problem is fans like the idea of the situation, but not the procedure and are worried that the hypothetical payoff is not worth it. The main differences between Romantic Couples and Moe Couplets are as follows:
- RC relationships bring conflict. MC relationships bring harmony and balance.
- RCs can bring out negative aspects of personalities. MCs bring out only positive ones.
- RCs are often 'conventional' relationships where the amount of intimacy is explicit. MCs usually are not consistent, even between episodes, by nature of the unusual individuals involved.
- Explicit RC information means the audience tends to settle onto an agreed 'canon'. and writers typically adjust their writing to appeal to this. MC audiences are not able to, giving writers maximum flexibility.
- RCs are usually designed to appeal to two different types of audience members. MCs are designed to appeal to the same one.
- RCs may consist of a new character who threatens to impede the established character's personality. New characters in MCs are usually nonthreatening and much more easily maintain the Status Quo.
Interestingly, the Moe Couplet often exists alongside an Official Couple, with the danger that if either overlaps, the audience might prefer one over the other. Occasionally, later installments featuring them might be hit with Character Exaggeration and actually gain official romantic overtones. Other times a show may be made up exclusively of Moe Couplets so Everyone Is Single.
In practice, only one of the characters really needs be designed like this, often a younger one whom the audience finds 'safe' and non-threatening. They are extremely popular in yuri and yaoi works, due to the natural maximization of Moe in the audience, but it's also present in other genres (particularly slice of life works that lack romance). The Wholesome Crossdresser (who is usually implicitly gay) has this relationship with shoujo leads. In shounen, a (usually unattached) female co-lead has this relationship with the male lead if he gets his official girlfriend outside his circle of friends. Couplets are also common gimmicks in designing an Economy Cast. See also The Not-Love Interest.
- Sasami and Ryo-Ohki from Tenchi Muyo!.
- Lelouch of Code Geass isn't exactly the most happy or stable person on the planet, and for good reason, but you wouldn't know it from his interactions with either Shirley or Nunnally. Either of the latter two bring out the softer and more light-hearted side out of the former, and are both inspirations behind the world he wants to create. Euphemia has a similar effect on the suicidal Suzaku. Which makes it all the more tragic when said Moe counterparts are Stuffed into the Fridge (with one exception, though the truth doesn't come out until it's too late), amongst other assorted mishaps, pushing both Lelouch and Suzaku past the breaking point.
- Twins L and R Nomura from Marginal #4. R is the more conventionally Moe one, while L is the most mischievous one. But L cares about R more than anything - possibly too much - and they become this.
- Lyar Von Ertiana and Kotoko-01 from Divergence Eve.
- Bleach: While Kenpachi Zaraki is the farthest thing you're gonna get from moe, pair him and Yachiru up, and their interactions are either funny or totally adorable.
- Mai Tokiha in Mai-HiME evolves into this. Leaving the Shipping Wars aside in regards to Yuuichi, her relationship with her brother Takumi shows off her mature qualities. Later iterations effectively pair her with Mikoto (a highly marketable but otherwise potentially annoying character) which lets her fully assume a motherly mode that doesn't conflict with her badassness and letting Mikoto's clingy qualities be endearing.
- Project A-ko: C-ko is small, cute, and vulnerable, which inspires A-ko to act as the protective "big sister" whenever she defends C-ko.
- In Slayers, Gourry does this for Lina. The show has more subtle romantic undertones, but Lina tends to react in surprisingly cute ways if she thinks Gourry is being particularly affectionate towards her. This happens with enough rarity it never affects her strong qualities as a shounen lead to any real degree and also doesn't squick the non-romantically inclined audience.
- Setsuna from Mahou Sensei Negima! emotes much in the same way Motoko from Love Hina does. Both are popular characters in their series, but Setsuna's affection towards a (controversially) oblivious character seem more tolerated by the fandom.
- Keiichi and Belldandy's relationship in Ah! My Goddess might qualify, creating the strange irony of essentially being married without an actual lack of relationship progression. Both get to emote to more-or-less harmless characters who are the least likely to exploit each other's selflessness.
- Nagisa has this relationship with Tamao in Strawberry Panic!, despite being in an Official Couple. Safe to say those not enamored of the Onee-sama archetype and the drama they bring often prefer her to Shizuma.
- Similarly, Yumi in Marimite has this kind of relationship with several characters compared to the one she has with Sachiko, leading to the fan-joke that Yumi could create her own Reverse Harem.
- Latvia and Sealand in Axis Powers Hetalia. Sealand helps Latvia not be a twitching emotional wreck and Latvia keeps Sealand grounded in reality.
- Also America and Japan. People who find America obnoxious and pushy at times and Japan dull compared to the rest of the cast often like them better after seeing their interactions together, with America drawing Japan out of his emotional reticence with his natural cheer and energy and Japan acting as the calm, mature foil to him. Even (and maybe especially) America/England and Greece/Japan shippers adore them as BFFs. However, actual romance fic for them is rare, probably because the harmony of their Opposites Attract friendship tends to go out of the window when people try writing them with romantic tension and Japan has a different type of Moe Couplet with Greece that translates much better to romance.
- As for Japan and Greece, while they may not have as obvious an Opposites Attract dynamic as Japan and America do, their similarities and more subtle differences in personality end up enhancing their Moe points. Not only are they both Kindhearted Cat Lovers, which has a built-in cuteness factor, but Japan can give off the subtle impression that underneath his stoic exterior lies a sweet, warm-hearted, and even shy soul without it being overwhelmed by louder personalities (and him possibly coming across as a less endearing/moe Stoic instead) when petting Greece's cats or simply being at ease with him, and Greece's laidback, easygoing nature makes him the ideal partner to patiently deal with Japan's emotional reticence and romantic/sexual awkwardness. Ironically, they're the only pair (mostly) confirmed to have had sex in canon, but the fact that most (and arguably, the best) fanworks for them focus much more on the tranquility and harmony of their dynamic than on sex, and that it's difficult to imagine Greece ever forcing himself on Japan or making him truly uncomfortable in spite of his Really Gets Around reputation, makes them a true Moe Couplet. (Not to mention that it's quite easy to write them as an established romantic couple without compromising their natural dynamic.)
- Not to mention Italy and Germany. Germany is rather intimidating, but he'd probably be a lot more so without Italy constantly demanding a hug or kiss or... something.
- Demonstrated◊ in Ouran High School Host Club.
- Lampshaded when Kasanoda makes it apparent that without Hunny, Mori is just as intimidating as he is.
- Sakaki and Chiyo in Azumanga Daioh, who often pair off. Sakaki comes off as intimidating, but really she's just shy and in love with all adorable things. Chiyo is a Cheerful Child who really wants to be an adult. When the team up, they cover each other's weaknesses and the Moe increases exponentially. Add in their pets, Tadakichi-san and Maya, and things get even better.
- Chiyo and Osaka also sometimes count, such as when Chiyo's overpowering cuteness and Osaka's gentle, slow-going pace lead to Chiyo in a penguin suit getting happily hand-fed by Osaka.
- Hayate the Combat Butler has this type of relationship between most of the characters, both of the romantic side sort and the non-romantic. Sakuya almost forces other characters into these with her thinking the world is a Boke and Tsukkomi Routine and tries to make many of the other characters her other half in them. Nagi with Isumi treads the line When they were young, Nagi forced Isumi to imprint a 'marriage certificate' and Isumi understands (and helps to expand on) Nagi's self-made-manga.
- Hayate himself is in several of these, not necessarily all in the romantic field, but strangely, he is the one whose moe factor is ramped up generally.
- Well-expressed in The Sacred Blacksmith, especially the ending theme. Lisa paired with any of the other characters increases her own moe and significantly brings out at least one trait of the other characters.
- Yutaka Kobayakawa and Minami Iwasaki from Lucky Star also counts, and it's probably an allusion to Chiyo-chan and Sakaki respectively from Azumanga Daioh as mentioned above. But it doesn't stop Hiyori Tamura activating her Shipping Goggles.
- Homura Akemi, with her experience and power, protecting the sweetly innocent Madoka Kaname in Puella Magi Madoka Magica, gains this quality as the series progresses. Even more pronounced in the original timeline where the roles are reversed and the gentle, but plucky and selfless Madoka is the one who protects the once-mousy and shy Homura.
- In Pokémon's 5th Movie, Ash and Legendary-of-the-film Latias have this trait in abundance. Despite the obvious Interspecies Romance, their interactions are so sweet and cute that AltoShipping is still a rather popular couple in the fanbase despite the movie having come out back in 2002.
- Haru and Kisa from Fruits Basket. Also Played With between Rin and Hiro, who are both pretty cynical and aloof, but are evidently concerned for one another.
- Ai Haibara from Detective Conan describes Sumiko Kobayashi and Ninzaburo Shiratori in terms that fit very well in this trope. When they actually get together, she turns out to be completely right.
Ai: "... I think they make a good couple. Kobayashi-sensei is a fan of mysteries and Inspector Shiratori might be able to tell her good case stories."
- Kobayashi and her surrogate daughter Kanna in Miss Kobayashi's Dragon Maid. Both of them are rather stoic, though their interactions tend to bring out each other's more emotional sides (whether it be Kobayashi's motherly instincts or Kanna's childish innocence).
- Any of the master/apprentice tandem in Aria. Any time one of the pair is the focus of a episode, it allow to see them bonding in a really sweet way, show the cutest sides of the younger one, and make the Cool Big Sis qualities of the older one shine the brightest. Especialy with Akira and Aika, as it show their "dere" side the best.
- Harley Quinn and Poison Ivy are occasionally treated like this by the fandom, partly due to their team-up being one of genuine friendship, a way of emphasizing strong female characters, and diffuses much of their underlying creepiness (Harley seeming more comedic than actually crazy, and Ivy being less misanthropic, etc.)
- This is why pairing Wolverine up with one of many younger female superhero compatriots, whether it's Kitty Pryde, Rogue, Jubilee, Armor, Katie Power, or Kamala Khan works so well. They soften Wolverine's image and bring out one of his few positive qualities: being an incredibly loyal Papa Wolf. He in turn helps them gain several badass points.
- Axis Powers Hetalia fanfic Gankona, Unnachgiebig, Unità: Italy brings warmth and joy to the tough and harsh Germany and the cold and calculating Japan.
- Mimi and Elle in Bird are a somewhat tragic take on the concept. Mimi has little control of her powers and is ostracized as a result. Elle has similar difficulties, but the worlds she creates are soothing or beautiful. However, she can't engage her peers easily because of her fugues. Mimi is the only one who engages Elle, and Elle is the only one that sticks with Mimi- even though they are dysfunctional and Mimi is sometimes physically dangerous.
- HERZ: Akiko is a chirpy, lovable, endearing little kid and Rei is her cool, detached, unemotional aunt. When they are together Rei shows her softer, warmer and more overprotective side and Akiko is more cheerful.
- The Second Try: Rei Ayanami of all girls and Aki, a lost child she finds wandering the streets of Tokyo-3 and ends up taking home with her. That kid's Cuteness Proximity Field is practically a superpower! Rei carries on with this trope in sequel web-manga Aki-chan's Life... In addition to being Aki's Cool Aunt, seeing as she's Shinji and Asuka's Kid from the Future.
- Rei and Teri in The Child of Love. Teri helped her find her emotions and rebel against Gendo, and Rei calmed Teri down when her niece went hyper.
- Corrin Reacts: Beruka and Benny are a downplayed example who help bring each other's better sides to the fore; Beruka's warmer side and Benny's more affirmative side respectively.
- Harry Potter: The title character has a this dynamic going on with two different girls (both of whom are shipped in Fan Preferred Couples with him).
- Harry and Hermione. Hermione is a magical genius, except when it comes to dealing with actual dark wizards, which is Harry's specialty (his life is basically a long series of fighting dark wizards). When it comes to personality, Harry is selfless to an annoying degree even when personal friends are not involved, while Hermione focuses on immediate gain and loss to her close friends (especially when it comes to grades!). While these traits alone would get kind of annoying, together they play off each other quite well, even without going into Shipping territory.
- Similarly, Harry and Luna. Luna is a Cloud Cuckoolander who hardly seems troubled by anything and helps her father run the magical equivalent of a tabloid magazine, while Harry becomes more traumatized as increasing numbers of his friends and loved ones die. Some of them right in front of him. Yet Luna understands what losing a loved one feels like, enabling her to empathize with his grief over Sirius—and Harry knows what being unfairly bullied feels like, so he naturally wants to help her out when people steal Luna's things and mock her behind her back.
- Imriel and Alais in the Kushiel's Legacy series. From childhood on each of the cousins see each other as an actual person, not a product of their parentage. It gets to the point where Imriel's interactions with Alais are the most consistently happy moments in his life.
- iCarly: Carly and Freddie. Pretty much everything they do as a couple is cute to the extreme.
- Odo and Kira from Star Trek: Deep Space Nine, who tend to soften considerably when they're around each other and generally bring out each other's good sides.
- Horatio Hornblower: This was part of the logic for including Archie Kennedy as a recurring character. Horatio tends to keep a lot to himself, and having a more expressive friend of his own rank and age gives Horatio someone he can open up to in a way that he can't with his superior officers or subordinates, and Archie's sarcastic tendencies make a good contrast with Horatio's more serious demeanor. The fact that Archie is a Woobie also gives the normally stoic Horatio a chance to express his deredere side through his concern for his friend.
- BioWare's Mass Effect games feature this, though by nature of being an RPG, it's up to the player to truly fulfill this trope. Regardless, Ken and Gabby in Mass Effect 2 have this kind of relationship. As for the optional, player-driven ones: Liara, Garrus, and Tali are the most obvious.
- So your job is to exterminate a bunch of little demon brainsuckers, and you've killed all but one egg, but then the egg hatches and thinks you are its mommy. Do you a) kill it anyway or b) become its adoptive parent (at least temporarily)? Samus chose option b.
- Of course, if she had killed it, she'd be dead, since it ate the unbreakable blocks that blocked her escape.
- Also, in Super Smash Bros. Brawl, there's Samus and Pikachu. In the adventure mode, Samus is trying to find her Powered Armor, and she finds poor little Pikachu being used to power a generator, so she breaks the cage. Later, after Samus gets her Powered Armor back, Ridley nearly kills her, but Pikachu saves her.
- Snake and Otacon. Otacon warms Snake up and restrains him from going over the edge, while Snake helped Otacon out of his shell and grounded him. The fact that all of their interactions from Metal Gear Solid 2 on are a barrel of cuteness hovering somewhere between Happily Married and Like an Old Married Couple doesn't hurt.
- Beta Couple Zuko and Mai from Avatar: The Last Airbender. Her Emotionless Girl crushed his emo Wangst in the first episode of Season Three in just one sentence, and from that moment on she was the natural antidote to his tendency to gloom, just as he was her natural antidote for her tendency to emotionally distance herself from everything.
Mai: I just asked if you were cold, I didn't ask for your whole life story.
- Doubly so in that at the end of the show, when they've both triumphed over their own respective issues above, Mai still provides the natural antidote to another one of Zuko's weaknesses — his enthusiastic political idealism could render him potentially vulnerable as Fire Lord, were it not for the fact that his Fire-Lady-To-Be is an icy pragmatist with the patience of a stone.
- Kim and Ron have their moments, especially when they were kids.
- Thundercats 2011 has Panthro and Ro-Bear Bill!
- Gus and Cornchip Girl from Recess