''[[http://www.fimfiction.net/story/27874 Xenophilia]]'', written by [[http://www.fimfiction.net/user/AnonAuthor AnonAuthor]] and published on Website/FimfictionDotNet by [[http://www.fimfiction.net/user/AnonponyDASHIE AnonponyDASHIE]], opens several months after [[MeaningfulName Bellerophon]] "Lero" Michaelides' unexplained arrival in [[WesternAnimation/MyLittlePonyFriendshipIsMagic Equestria]]. Despite missing his home and family, Lero has adjusted well -- he has multiple paying jobs, a nice house, and a close friendship with Rainbow Dash. Said friendship gradually grows into love, but Lero fails to pick up on it until Rainbow impulsively kisses him in the opening chapter. The relationship soon escalates into explicit human on pony sex scenes.

From here, the story follows Lero and Rainbow Dash's relationship through Rainbow's eyes as they both attempt to understand and adjust to each other's cultural and social norms. Particular focus is given to Equestria's tradition of polygamy, (a necessity given the male-to-female ratio) where the lead mare of a herd will set her stallion up with unattached mares.

This story has since spawned a large amount of RecursiveFanfiction, (though some have partially involved the original author): a ScrapbookStory [[http://www.fimfiction.net/story/57315/The-Xenophile%27s-Guide-to-Equestria sequel]] -- written in-universe by Twilight Sparkle -- [[http://www.fimfiction.net/story/103616/xenophilia-shotglass-oneshots numerous]] [[http://www.fimfiction.net/story/62265/Xenophilia%3A-Side-Stories collections]] of [[http://www.fimfiction.net/story/67231/xenophilia-further-tales side stories]], and a [[FanFic/DividedRainbow spinoff saga,]] all in progress and set at various points in the timeline, and [[http://www.fimfiction.net/story/78569/xenophilia-what-came-before several]] [[http://www.fimfiction.net/story/62374/xenophilia-side-story-cultural-norms one-shots]]. The series has had a large influence on Friendship is Magic fan fiction due to its popularity, with elements from the story increasingly being [[ShoutOut referenced]] or [[FollowTheLeader borrowed]] in other works.

The following RecursiveFanfiction also have their own pages:

* ''FanFic/DividedRainbow''
* ''FanFic/IntoTheHedge''
* ''FanFic/{{Xenophoolia}}''

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!!''Xenophilia'' and its spinoffs contains examples of the following tropes:
* AbortedArc: After {{the Reveal}} that {{the Fair Folk}} were likely responsible for bringing Lero to Equestria, the plot point ends up being abandoned when the story finishes soon after, due to the author [[RealLifeWritesThePlot losing inspiration]].
* ACupAngst: The pony equivalent. Rainbow having a lack of 'bounce' to her flank, combined with her strength and musculature ends up causing many stallions to ignore her or blow her off for more attractive mares, and leads to some serious self-esteem issues about her appearance.
* AdaptationalBadass: Lyra Heartstrings, who is described by Rainbow Dash as a grandmaster of a unicorn martial art called Still Way, one of the five or six most dangerous ponies in Equestria including the princesses, and the only pony in town besides Twilight who could take Rainbow in a serious fight.
* ADayInTheLimelight: The side-story "The Weak Lyre" is told from Lyra's perspective.
* AuthorAppeal: A chestnut soup recipe appears in ''The Xenophile's Guide to Equestria'' for seemingly little reason other than because the author... [[CaptainObvious likes chestnuts]].
* {{Badass}}: Rainbow is already this in canon, but is also one of the few pegasi strong enough to learn earth pony martial arts.
* BadLiar: Rainbow Dash does does an extremely poor job of denying her feelings for Lero, and repeatedly ends up giving the game away almost instantly when questioned.
* BalancedHarem[=/=]SupportingHarem: Played with. In modern Equestria it's common practice to not favour one member of the herd over another, something which Lero tries to adhere to. However, Rainbow Dash receives more prominence in the story and - despite being considered an antiquated custom - is viewed as the lead mare in the herd by Twilight and Lyra, something which Rainbow personally detests.
** Lero explicitly says at one point that Rainbow "will always by my favorite." Twilight and Lyra don't seem to mind, as long as they get plenty of attention too.
* BerserkButton:
** Rainbow Dash is fiercely protective of Lero, and reacts with fury when he brings up a highly offensive misandrist comment made to him months earlier.
** Mares as a whole are extremely protective of their stallions, with even the slightest perceived threat triggering this.
* BestialityIsDepraved: In-universe, Honeydew, Honeybee, Honeysuckle and Glitter Dust antagonise Rainbow Dash over her relationship with Lero, calling her a "monkey-lover".
* BewareTheNiceOnes:
** The stories note to the point of exhaustion that Lero is quite a bit more frail and weak than all kinds of ponies, a fact he himself is all too aware of. However, as one chapter in the main story demonstrates, he can easily strangle a unicorn out of channeling a spell... and that's without trying to cause any real damage.
** Lyra as well. After Rainbow tells the others about Lyra's martial arts background:
-->'''Lero''': Wow. I had no idea. She’s always been really friendly to me.
-->'''Rainbow Dash''': Yeah, I've heard that about her. ''Total'' sweetheart, you'd never guess that she could kill you in half a second from like three hundred bodylengths away.
* [[BizarreAlienBiology Bizarre Human Biology]]: Several characters are utterly perplexed by human males possessing nipples. The strength of Lero's hands also surprises many ponies who expect them to be extremely fragile.
* BoldlyComing: Did you really expect otherwise from a story titled ''Xenophilia''?
* CallForward: In Chapter 11 of ''The Xenophile's Guide to Equestria'', Twilight's mother advises her against trying to construct a hypothetical model of Lero's social structure. "I just hope you didn’t do something silly like try to construct an analogue of his society by mixing up a pastiche from the descriptions in Aggie’s book." As seen in Chapter 8 of ''Xenophilia'', this is exactly what she did.
* ConvenientlyCommonKink: Although perhaps it's not surprising that both Twilight Sparkle and Rainbow Dash enjoy playing characters from a book. Some aversions, though, as there are some things that are uncomfortable or take some adjustments.
* CuddleBug: Mentioned by name. Twilight is extremely amused to discover that Rainbow Dash is secretly this in private.
* CultureClash: Lero, a human from a patriarchal society ends up stuck in a matriarchal world with [[ValuesDissonance completely different values]]. Exploring the problems this throws up is a major theme throughout.
* CurbstompBattle: Any time Lyra gets involved in a fight. The only battle we see on-page ends with Lyra winning a flawless victory in a matter of seconds, to the shock of all witnesses.
* DeadpanSnarker: Rainbow and Twilight as per series canon, but Lero and Lyra have their moments as well.
* DescriptionCut: When Celestia finds about Lero and Rainbow Dash's close friendship, she writes back saying that she's sure Twilight and her friends will handle the delicate situation with the "same tact and sensitivity that I and my sister would surely display." Meanwhile, Luna writes to Twilight asking to enter Applejack's pool, with an opening wager of ten bits on successful consummation within a month. Celestia is not impressed when she finds out.
* DestructoNookie: Between Twilight and Lero after a fight. What precisely happened isn't mentioned, but Twilight does note afterwards that they'll need to buy a new bed.
* DisproportionateRetribution:
** Rainbow Dash threatens to make it permanently rain on Twilight to make sure she keeps Rainbow's CuddleBug tendencies a secret.
** Celestia threatens to teleport Lero into space when he first arrives to [[SecretTestofCharacter see how he'd react to threats]].
* DistractedByTheSexy: A common problem with mares in heat, resulting in them isolating themselves until it's over.
* DoubleEntendre: Rarity is apparently a master of this, and often uses it as a means to make Rainbow Dash feel embarrassed.
* DreamWithinADream: Happens to Rainbow Dash in the side story "Living the Dream". Whether the dream is a [[DreamingOfThingsToCome vision of the future]], or merely [[AllJustADream just a dream]] is [[ShrugofGod left to the reader to decide]].
* [[EveryoneCanSeeIt Everypony Can See It]]: Rainbow Dash's crush on Lero isn't a secret to anyone except Lero, and once the two get together, Twilight and Applejack very quickly figure it out.
* [[EveryoneHasStandards Everypony Has Standards]]: Applejack and Lero may not always see eye to eye, but even she is ''furious'' when she finds out he was on the receiving end of an incredibly offensive sexual slur from another mare. Even offering to kick that mare's teeth in.
* [[EveryoneIsBi Everypony is Bi]]: Almost everypony, with Rainbow Dash being a notable exception. To the point where Rainbow Dash [[LanguageEqualsThought can only describe her lack of interest in other mares as 'bent' or 'weird']], although individual acts can be gay or straight or not.
* ExoticEquipment: While not as exotic as a typical example of this trope, Lero's appearance and how it differs from a stallion does cause some surprises for ponies.
* ExoticExtendedMarriage: Due to Equestria's disproportionate female-to-male ratio, monogamy is considered selfish and most stallions end up in relationships with three mares, more if there's another stallion involved.
* EvenEvilHasStandards: No character is strictly evil per se, but after being saved from drowning Honeybee is at least grateful enough to thank Lero, and promises to leave him and his herd alone in future.
* FantasticArousal: Wings and flight muscles for pegasi. Unicorn horns as well, but only under certain circumstances.
** And only for some unicorns: Rarity says it never did a thing for her.
* FantasticRacism: Honeydew, Honeybee, Honeysuckle and Glitter Dust towards Lero.
** The attitudes of the first three are fleshed out a bit in the side story "Fish Out of Water" - Honeysuckle and Honeybee are disgusted by interspecies mating, but Honeysuckle doesn't enjoy being mean as much as she let on earlier, and Honeybee is a decent enough pony to leave them alone after Lero saves her from drowning. Honeydew remains a full-on {{Jerkass}} though, giving the impression that her sister's life is worth nothing to her.
** Bon-Bon's mother is stated to have been an outright [[NobleBigot Noble Tribalist]], unwilling to hire unicorns to do a job even if her lack of hands or magic made doing the work herself nightmarish. She was still perfectly nice to Lyra, a unicorn, as her daughter's friend, though. It's implied to be a frustratingly common attitude, albeit one thankfully fading with time.
* TheFairFolk: Hinted at being responsible for bringing Lero to Equestria.
* FantasyContraception: Rainbow Dash actually worries about pregnancy when she first comes into heat, despite the [[InterspeciesRomance blindingly obvious reason that's not a matter of concern]].
* FeeFiFauxPas: Lero starts the story with absolutely no idea of Equestria's concepts of private behavior, then learns body language from a pegasus that's got the hots for him. Among more minor mistakes, he practically gropes Rainbow Dash in public without realizing that certain types of preening aren't done in public, and in another story doesn't realize that romantic nuzzles are romantic and then does the Equestrian equivalent of making out with everyone he meets until corrected.
* FishOutOfWater: Lero, who goes from a modern patriarchal society to a matriarchal medieval fantasy world run by ponies. It still throws up problems from time to time, but he adapts fairly well.
* FollowTheLeader: Since being published, several elements of Xenophilia's world have been used in other works.
* FootnoteFever: ''The Xenophile's Guide to Equestria'' makes extensive use of footnotes, as you would expect from what is an academic work in-universe.
* FreakinessShame: Owing to a combination of factors, Rainbow Dash has a very low opinion about her appearance and comes to view herself as a freak. Lero strongly disagrees with this assertion.
* GenderRarityValue: Mares outnumber stallions about four to one in the general Equestrian population, and Ponyville is closer to eight to one. Unusually, there's a mix of forms of this trope: while stallions have a good deal of social power and thus are worshipped in some ways, they historically have lacked political or economic power and were either possessed by mares or at least used for labor.
* [[GoodPeopleHaveGoodSex Good Ponies Have Good Sex]]: And very frequently too, it seems.
* HandyMan: In addition to massage, Lero's hands are sought for fixing the plumbing and various other hard-to-reach maintenance issues, earning him respect and acceptance from all but the most stubborn of ponies. Given the gender roles, probably also an example of a WrenchWench. Spanner Stallion?
* HeadTiltinglyKinky: Rainbow shows shades of this, being very willing to push the envelope and try new things. Twilight in comparison is much more reserved and reluctant to try what is [[ValuesDissonance unusual]] [[YourNormalIsOurTaboo behaviour]] for ponies.
* [[HeroesWantRedheads Heroines Want Redheads]]: Lero is redheaded, and has managed to attract [[{{Badass}} three]] [[CuteWitch heroic]] [[IKnowKungFu mares]].
* [[HumansThroughAlienEyes Humans Through Pony Eyes]]: The main story is told from Rainbow Dash's point of view, and the spinoff ''The Xenophile's Guide to Equestria'' is written by Twilight and features a variety of ponies' perspectives on Lero. Lyra also gets a chapter in the side-stories.
* HypocriticalHumour: When Twilight writes to Celestia about her friends' suspicions of a relationship building between Lero and Rainbow Dash, she criticises Applejack for suggesting a pool on the outcome of their time together, which she thinks is a terrible thing to do to a friend. As such, she put herself down for no more than three bits on the spread.
** Given the nature of the bet it's possible to infer that she had to ''make up reason to have the spread'' before she could place money on it.
* InterspeciesRomance: The ramifications of which are the entire point of the story.
* IfItsYouItsOkay: As she is not attracted to other mares, Rainbow Dash's growing feelings towards Twilight cause her much confusion before she ultimately accepts that love is love.
* TheImmodestOrgasm: Twilight can be rather vocal on occasions, though it is implied she's managed to tone it down after complaints. Apparently this trait runs in the family, to [[TooMuchInformation Twilight's dismay]].
* InnocentlyInsensitive:
** While she doesn't intentionally hurt her friends, Rainbow Dash does have an unfortunate tendency to put her hoof in her mouth.
** Lero. Despite being very good at defusing situations with words - something Rainbow Dash often takes advantage of - there are times where his lack of knowledge of local customs ends up inadvertently upsetting others.
* InSeriesNickname: Lero tends to collect these, affectionately being known as "Big Guy" to Rainbow, "Fingers" to Lyra, and "Mr. Handy" to Applejack.
* [[LikeASonToMe Like A Daughter To Me]]: Celestia privately worries about Twilight's choice in romantic partners, partly because she's the closest Celestia has had to a daughter in a very long time.
* LoveHurts: Having had a bad experience with romance in the past, Rainbow Dash's feelings for Lero cause her much pain until she learns that he does reciprocate them.
* MagiTek: Twilight invents several devices by combining some of the principles behind human technology with magic, with her recording device being the most prominent.
* TheMatchmaker:
** Rarity and Twilight are both this towards Rainbow Dash, and encourage her to express her feelings for Lero.
** Celestia later encourages Twilight and Lyra to try and court Lero.
** Mares in general engage in this as a solution to the lack of stallions. See ShipperOnDeck.
* MeaningfulName: Bellerophon will be a familiar name to those who know their Greek mythology, notably for his [[GeniusBonus exploits in taming Pegasus]].
** {{Lampshade|Hanging}}d by the narration as the result of parents who had been "odd folk".
* MorningSickness: Proves to be somewhat disruptive to Lyra's training regimen in one of the side stories. Good thing Lero is there to hold her mane back when it does.
* MundaneLuxury: Owing to his fingers, Lero's skills as a masseur are this for ponies, to the point where his schedule is booked for weeks in advance.
* MuscleAngst: Female version. Rainbow's exceptional strength for a pegasus and stallions' reactions to it gives her a very poor body image. It doesn't help matters that her strength ended up causing her father to wonder if she really was his daughter.
* NerdsAreVirgins: Despite being in another herd at one point, Twilight was too shy to ever do anything other than watch, and later she was too busy as Celestia's protégée to ever bother with romance.
* NetworkToTheRescue: The author of ''Xenophilia'' originally posted the beginning of the story in an obscure little corner of the internet and seemed content to leave it there. Only after urging from supporters was it continued, leading to the massively popular and successful universe it has become.
* NiceGuy: Lero, who is very willing to help others, as well as being extremely friendly and patient. Just don't provoke him [[BewareTheNiceOnes too much]].
* [[NoGuyWantsAnAmazon No Stallion Wants An Amazon]]:
** Prior to meeting Lero, Rainbow Dash was very unlucky in the romance department, owing to her strong musculature and slender appearance.
** Averted with Lero, who shows no issues dating anyone much stronger than him. While he doesn't specifically [[AmazonChaser seek out]] strong mares, it is noted that he's managed to attract several of the most dangerous ponies in Equestria.
* ObliviousToLove:
** Lero, for several weeks prior to the first chapter, partially as a result of his lack of knowledge of Equestrian culture and social cues. It's especially apparent in the side-story "Living the Dream".
** Rainbow herself doesn't figure out that Lero does reciprocate her feelings until he kisses her back.
** Twilight also falls afoul of this, and at several times becomes convinced that Lero has no interest in her or wants to kick her out of the herd. Partly because she misunderstands human body language and customs, and partly because, hey, this ''is'' Twilight.
* OutWithABang: Referenced. Rainbow mentions that, [[ItMakesSenseInContext if she ever did kill Lero]], it would be through this, and be "the most awesome way to go ever".
* ParentalAbandonment: Rainbow Dash's mother runs away while she is still a foal, leaving her to be raised by her father.
* PlatonicLifePartners: Lyra and Bon-Bon. Lero initially mistakes them as a couple, but in their own words they simply have a very close sisterly relationship.
* {{Polyamory}}: Customary in this version of Equestria, due to the higher percentage of mares than stallions.
* {{Prequel}}: The side-story "Living the Dream", set shortly before the main story.
* PrimalFear: One reason why Lero is shunned by many ponies when he initially ends up in Equestria is for fear he'll eat them. For the most part this disappears after he makes friends and earns the respect of many of the town's residents.
** When this concern is brought up he is so visibly horrified by the thought of eating something intelligent it brings a bunch of ponies over to his side.
* PunnyName: Played straight in both directions.
-->'''Star Sparkle:''' Is everything on your world a nonsensical parody of this one?
* PunyEarthlings: {{Discussed|Trope}}. As a result of being placed in a culture where [[ValuesDissonance females seek to protect him]] and where he is viewed by almost everyone as weak and fragile, Lero finally snaps when threatened and lectures his would-be attacker that just because he isn't as strong as a pony, it does ''not'' make him helpless. Said discussion takes place as [[NeckLift he's holding the would be attacker up in the air by her throat]], only not hurting her because he doesn't want to, as he most certainly ''can''.
* SecretTestOfCharacter: When Lero first arrives in Equestria, Celestia tries to goad him into getting angry, and then threatens to teleport him into space to see how he reacts under stress. She is very apologetic afterwards however.
* SexSlave: As a result of the matriarchal culture, stallions usually ended up being used as little more than this in the past, until the princesses put a stop to the behaviour. Apparently FetishFuel in-universe for some, to Twilight's disgust.
* SickeningSweethearts: While they try and keep their relationship private and low-key, Lero and Rainbow Dash display this from time to time, often to the embarrassment of the latter.
* ShipperOnDeck:
** Mares have a tendency to engage in this in-universe due to the gender disparity. Rainbow Dash points out to Lero that if they didn't do this, it would result in a lot of unhappy and lonely ponies.
** Twilight's recorder also seems to be very keen on shipping Lero with Shining Armour.
* ShownTheirWork: Say what you will about this story, the author has taken the trouble to read up on herd behaviour in RealLife horses.
* TheSmartGuy:
** Lero certainly isn't a slouch in the brain department, despite not being quite at the same level as Twilight.
** Lyra is pretty intelligent and rational as well, even if she comes across as more of a WarriorPoet.
* [[StayInTheKitchen Stay In The Bedroom]]: {{Inverted|Trope}}. Lero mentions having once been asked by an unidentified mare why he was out on the street instead of in the bedroom or in the fields. Applejack, Twilight and especially Rainbow Dash are ''livid'' when they hear it, more so than Lero himself.
* SuperDrowningSkills:
** According to Rainbow Dash in the side story "Fish out of Water", ponies either fall into the category of capable swimmers or being completely unable to swim at all with no middle ground, most in the latter group.
** Lero is also initially believed to fall into this category due to the poor swimming abilities of apes, but he quickly proves them wrong.
* TechnicalVirgin: Using a 'cooler' isn't gay. Or even really count as sex. Doesn't matter that two mares who are in love might do the exact same physical thing.
* ThreeWaySex: Fairly common within herds. Due to polygamy being usual behaviour in Equestria, this doesn't have the same connotations as in [[ValuesDissonance human culture]].
* TooDumbToLive: Honeydew, who ends up threatening [[{{Badass}} Rainbow Dash]], [[BadassBookworm Twilight]], and [[AdaptationalBadass Lyra]]. The last one [[CurbstompBattle doesn't end well for her]].
* TrappedInAnotherWorld: Lero. It's also suggested he was stuck in another world before somehow escaping to Equestria.
* UncannyValley: In-universe, regular horses tend to fall into this for most ponies due to the facial expressions.
* UnusualEuphemism: Referring to a stallion as a "saddleblanket" is extremely offensive and implies he is being courted for amusement.
** Literally something a mare would use "to keep her back warm".
* UnusuallyUninterestingSight: Lero is quite the oddity in Equestria, and seemingly everypony has an opinion on him one way or another... Except for Applejack, who [[NoBigDeal never really seems to care.]]
* ValuesDissonance: In-universe, this affects a lot of Rainbow and Lero's relationship, as well as Lero's interactions with other characters. Exploring these differences and Lero attempting to adapt to them is an integral part of the story.
** In particular, Lero's attitude towards nudity causes much confusion for ponies and is frequently brought up.
** Human patriarchal culture, and specifically the concept of males defending females, becomes a repeated CultureClash when in a society where the men are supposed to be defended by women. Lero standing up for his mares rapidly escalates even small problems into major disasters as the nearest mares want to defend their stallion.
** Twilight's attempts to compensate for this when she tries courting Lero and Rainbow Dash fail spectacularly, as a result of her trying to extrapolate human culture from gryphon and dragon behaviour.
* VitriolicBestBuds: Lero and Rainbow Dash both enjoy verbal sparring with each other, and each gives as good as they get.
* WackyCravings: Poor Lyra...
-->Why did she always end up eating fish? She didn’t even like fish and it had certainly never agreed with her. And why could she not talk to Daisy Jo the cow for more than five minutes without salivating these days? And why were the pigs over at Sweet Apple Acres looking so... '''tempting'''?
* WarriorPoet: Lyra. The story makes several references to her martial art skills and role as an auxiliary guard, but she can more often be found quoting philosophy and poetry, or dispensing sagacious wisdom.
* WeakButSkilled: Lero. While physically far outmatched by even the weakest pony, human physiology gives him a large advantage over ponies in several skills, and allows him to hold his own in a variety of sports. And he certainly isn't helpless in a fight.
* WhatTheHellHero: Twilight delivers a mild one towards Celestia when she sees how scared Lero is of her, something which isn't ''completely'' Celestia's fault. Twilight is also pretty shocked when she discovers that Celestia threatened to teleport Lero into space [[SecretTestOfCharacter to see how he's react]].
* [[WouldntHitAGirl Wouldn't Hit A Stallion]]: {{Inverted|Trope}}. Due to the reversed gender roles, hitting a stallion is something most mares would never do. The behaviour is so ingrained that when Lero is threatened by Shimmer, Rainbow Dash after the event is very skeptical that she would have actually gone ahead and done it.
* {{Xenofiction}}: The story is told mostly from Rainbow Dash's perspective, with some chapters being written from Twilight or Lyra's point of view. The completely different instinctual reactions and thought-processes of ponies plays a very large role in the setting.
* TheXenophile:
** While not played up to the same degree as elsewhere, Lyra does come across as quietly fascinated by Lero.
** Twilight is also very interested in Lero, but tends to treat it more as another [[ForScience science project]] than anything else.
* YourNormalIsOurTaboo: A common issue. Public nudity is a common aspect of pony culture, to the point where concealing clothing is somewhat stigmatized as related to menial labor. Grabbing a mare's chest isn't anything unusual, but touching a pegasus on the wrong part of the shoulder is scandalous in public. "Dolphin-style" as a position is uncomfortably kinky. A mare should never let the stallion pay for a dinner date.