[[http://www.fimfiction.net/story/877/Under-The-Northern-Lights ''Under The Northern Lights'']] is a WesternAnimation/MyLittlePonyFriendshipIsMagic fanfic written by sieurin (who calls himself Nattam on fanfiction.net). Princess Luna travels on a diplomatic journey to the cold reindeer kingdom Tarandroland, since reindeer pirates use it as a base to plunder northern Equestria. She brings with her Twilight Sparkle and Spike for help and companionship. The mission turn out to involve more action that politics, and, to quote the descriptive summary, Luna & Co have to deal with: "scheming unicorn courtiers, unfriendly surly reindeer, bloodthirsty pirates, ancient sorcery and dangerous monsters", not to mention old magic and beings born before Luna and Celestia. Every year, the reindeer have to ''fight'' Winter to make it go away - but this year it seems the battle is lost already in autumn... Is it possible that this time Winter might win for good?

The story is a rather episodic fantasy story of the epic sort, with much WorldBuilding, not just for the country of Tarandroland but for everything from Equestrian comic books to the elder relatives of Luna and Celestia. It is ongoing, and until finished this page represents the unfinished story.
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!! Fanfic/UnderTheNorthernLights contains examples of:
* TheAlcoholic: King Ukko is a bitter drunkard. Heavy drinking is socially mandated among reindeer, but he does it enough that even they react negatively.
* AlternateCharacterInterpretation: In-universe. The reindeer have very different views from ponies (and viewers/readers) on the main six. The reindeer believe the Main Six are Celestia's personal wetworks squad, a team of hand-picked elite troubleshooters led by "the most powerful and evil sorceress in the world", who make all major sources of unrest in Equestria "go away", and let Celestia be the benevolent ruler of a perfect little sugar bowl as far as everyone else is concerned.
* AnachronismStew: The author refers to his world-building as "anachronism gumbo". It begins in the early chapters where a seer "predicts" her goddess will return to her people by seeing it on TV, and Viking-like raiders loot electronics along with food and cloth.
* [[AnIcePerson An Ice Wyrm]]: Nidhoggs are limb-less dragonlike monsters who breathe ice cold instead of fire. They primarily use it to deep-freeze wood and then eat it.
* BladeOnAStick: Most reindeer who travel during the winter do so on skis, and use a single ski-staff which has a spearpoint (used for MundaneUtility as well as stabbing enemies or monsters). The legendary hero Sampo is said to have owned a magical spear. The informed opinion is that he must have owned a spear, since he was a reindeer warrior-noble, and as such he might have had it enchanted, but nothing is known. The Kings of Tarandroland carry a spear that is ''said'' to be Sampo's spear, but is a modern replica. It is enchanted, but mostly with a bunch of redundant magical attacks that are described as less than useful.
* BlindSeer: Inverted. Reindeer Sight is dependent on their eyes working. Eira is slowly going blind, and hence ''losing'' her clairvoyant ability.
** The reverse is also true, if Sight is disrupted, a reindeer will be unable to see.
* CarryABigStick: The [[OurTrollsAreDifferent stalu]] Kvalhissir keeps a huge mace which looks like a small tree whose roots grab a huge rock.
* [[ChekhovsGun Chekhov's Party Grenade]]
* CultureClash: Reindeer have a very negative view of magic and have problems with unicorn-heavy Equestria. Equestrians get nervous with both casual violence and the use of animal products, both common in Tarandroland.
* DarkIsNotEvil: Part of the philosophy of the Temple of Hrimfaxi, along with "darkness is necessary".
* TheDragon: Twilight prepares to speak up when she overhears reindeer protesting about 'her' being here, thinking that they were objecting to Luna. [[spoiler:Nope; Skinfaxi's Shadow is the greatest sorceress in Equestria, Twilight Sparkle.]]
* EldritchAbomination: Luna's and Celestia's great-uncles and great-aunts are described in a vision as "lights…sounds…patterns of magic in a black sphere that itched the brain and made the soul cry". They decided the laws of nature, seemingly on a whim. The only hostile one seems to be Discord, though, and his reality warping powers are presumably because he never agreed to what his siblings decided.
* EquivalentExchange: It is a central pillar of the reindeer world view that there is a downside to everything. They don't trust magic because they think there has to be a [[PowerataPrice price]] being paid by someone, even if it isn't the caster. They are wary of Equestria partly because it is such a nice place that whatever the downside is, it must be [[FalseUtopia horrible]].
* EvenEvilHasStandards: [[spoiler: Wiglek might be into cervine sacrifice to try and please Nightmare Moon, but he doesn't think highly on her betraying her own sister, calling her a "kinbetrayer" and "kin-slayer"]].
* FantasticNuke: In a ShoutOut to FalloutEquestria, "balefire bombs" are mentioned. They are theoretical weapons that have never actually been employed in war.
* FantasticRacism: Ubiqutous. Ponies about reindeer, reindeer about ponies, the zebra Paki about both categories, etc. In many cases it is not just mutual prejudice, it is also relatively low-key and consists of misunderstanding and underestimating the Other rather than outright oppression. The latter happens, though. Reindeer treat the Russ (immigrant dwarf Earth ponies) and the Urox (native aurochs) as second-class citizens, and we learn that ponies used to do the same to cattle, sheep and so on, who used to be slaves. Not everyone is racist over the board, either: the pirates of the ''Crimson Kraken'' are happily multi-cultural, but have a very negative view of "primitives" like the reindeer and the ponies from Tropical Island.
* FantasyCounterpartCulture: Tarandroland is a mix of modern and medieval Scandinavia. The nomadic "Grazer" reindeer are obviously a counterpart to the Sami people, though with much more power and influence. Unlike modern Scandinavia, Tarandroland is pretty much a third world country, however. There are other examples: "camel sultanates" and ki-rin ruled by a "Mikado" are mentioned, and Equestria is treated as similar to [[{{Eagleland}} USA]].
* GrimUpNorth: Tarandroland is cold and gloomy and the inhabitants are (at least stereotypically) gloomy and violent with tendencies to alcoholism.
* HoldYourHippogriffs: Common, just like in the canon show, but even more is added since the fic deals with more than one species. Get used to "anydeer" as well as "anypony".
* HornyVikings: The reindeer, at least those living on the coast, are a FantasyCounterpartCulture to the Norse. Going a-viking hasn't been common in a long while, that they start off again is the reason for Luna's mission. No actual horns are needed due to their antlers.
* IHaveManyNames: Reindeer know Luna and Celestia as Hrimfaxi and Skinfaxi. Stalu call Luna Daggmule ("dewmuzzle").
* ImagineSpot: Saga and Luna has some.
* LadyOfBlackMagic: Twilight is seen that way.
* LovableJock: Prince Vigg can be an immature brat but is usually quite a nice guy. His greatest interest seem to be winter sports, mostly skiing both cross-country and down-hill. He and his friends have apparently invented the snowboard as well.
* MeaningfulName: Many. "Saga" can mean both "seer" and "fairy tale": Saga has flights of fancy and is an actual seer. Lord Eminence is a gray unicorn: an "éminence grise", gray eminence, is someone having political power behind the scenes or informally, which is what Lord Eminence tries to achieve.
* MustHaveCaffeine: A cultural trait of the reindeer of Tarandroland. It is also KlatchianCoffee, at least according to Spike. This is of course because their real life [[FantasyCounterpartCulture counterparts]], the Scandinavians, are heavy coffee drinkers.
* MyGodWhatHaveIDone: The spy [[spoiler: Lord Eminence]] when he realizes that his plot has been found out because he has been very careless [[spoiler: because his special talent for being unobtrusive and even turning invisible doesn't work on reindeer, meaning there are lots of witnesses to his acts]]. He acted alone, convinced his success would force his superiors to accept a job well done, but Princess Luna is not only against the plan per se, she is also furious that he was so careless as to be found out. He doesn't say the actual phrase, but falls to the floor and moans [[OhMyGods "Mare in the Moon!"]] which prompts Luna to chastise him further for taking her name in vain when she is standing ''right there''.
* NightmareFetishist: Saga and Luna. It seems to be the proscribed aesthetics in the Temple of Hrimfaxi, which looks like a "haunted stable on Nightmare Night" according to Twilight Sparkle.
* NorseMythology: Ruthlessly plundered for names and concepts such as forest-eating wyrms called ''nidhoggs'', squirrel-like gossip-spirits called ''ratatosks'' and hostile wolf-people tribes known as ''Skolls''.
* OhMyGods: Twilight swears by Celestia's [[MemeticMutation socks]]. Also, Luna admonishes a swearing pony for "taking my name in vain" while she is standing right next to him. The temple-fawn Saga swears "Oh My Goddess" - the goddess in case being Luna.
* OurLichesAreDifferent: [[spoiler: Wiglek the Wicked]] was infused with a piece of the Nightmare while still alive, which turned him into a Lich when he died. He had asked to live forever when making a DealWithTheDevil with [[spoiler: Luna, when she was on her way to become Nightmare Moon]], but was screwed over ("[[ExactWords you will never die]]") and made into potentially undead instead.
* OurTitansAreDifferent: Luna's and Celestia's "aunts" and "uncles" (and presumably, parents). They are vast elemental beings which created the world and its intelligent species (learning the latter from the much younger Luna and Celestia [[spoiler: when their toys turned into the first ponies because the sisters loved them so much - so yeah, ponies originated as toys of two little girls]]). The one we have seen in the fic is the water being called Karhu-Akka by reindeer. She combines traits of bear, cow, squid and whale and now sleeps in the shape of a huge glacier. If she awakes, horrible things will happen. [[spoiler: Her rolling over in her sleep when Discord got free is one of the causes for the crisis in the fic, one which might kill all life in a country.]] Luna, however, remembers her as a kind aunt who played with her and Celestia by the sea and gave them wonderful toys.
* OurTrollsAreDifferent: Tarandroland is home to trolls called Stalu (after a Sami myth in real life). They are huge, misshapen cervines who live deep in forests and use forest lakes for gardens. They are infamous for eating reindeer. [[spoiler: They are actually moose, driven to hiding after the genocidal efforts of the reindeer. While they might be hostile in self-defense, they most certainly don't eat people.]]
* PerkyGoth: Saga is a NightmareFetishist with a love for dark heavy makeup and macabre jewelry who works as a temple maiden in a temple to a goddess of night and darkness. She is also chirpy, happy and carefree most of the time, Spike even calling her a "goth [[GenkiGirl Pinkie Pie]]". She claims that "goths are posers" so she probably wouldn't like the moniker herself.
* PirateGirl: Crimson Coat (actual name Sudden Gale), captain of the ''Crimson Kraken''. A renegade Equestrian Pegasus, she is not a nice mare: besides being a violent criminal she can add casual racism and sexual molestation to her resumé.
* ThePowerOfFriendship: Unsurprisingly a theme, although focused on the groups of Vigg, Spike, and Saga or Ukko's True Companions. Parodied when Twilight Sparkle, while pretending to be an Evil Sorceress, receives the Mother of All Friendship Musicals from Princess Ljufa.
* PublicDomainArtifact: The Sampo, from Finnish myth, occurs in Tarandroland myth as well in a similar form. The hero who used it became known as "Sampo", his actual name forgotten.
* RedBaron: Twilight Sparkle is called "Skinfaxi's Shadow" by the reindeer.
* RoyalsWhoActuallyDoSomething: Luna (as well as Celestia, but we se very little of her). Princess Ljufa, though her work is equally off-stage. Prince Vigg ''wants'' to be one, but his family thinks he should grow up and get an education first (he's only fifteen). The only titled person we see who doesn't work much is King Ukko, and that's because he is an alcoholic who spends his days either drunk or hungover. [[spoiler: He sharpens up later in the story, when his life and throne are directly threatened. ]]
* RunningGag: "Artifact means a magical thingamajig!" "I know!" Among others.
* SadlyMythtaken: Within the story. The Equestrian comic book hero ''Sampo the Warrior-Prince'' is based on the mythical Tarandroland hero Sampo. Based ''very loosely'' it seems. (The comic spoofed is rather obviously TheMightyThor.)
* ShoutOut: Twilight mentions when some of her friends met [[FanFic/ItsADangerousBusinessGoingOutYourDoor some deer]]
* SimilarSquad: King Ukko and his five companions are pretty similar to the Six Bearers of the Elements of Harmony, though Ukko & Co are male, reindeer and old enough to be grandparents, of course. Twilight and Spike wonder about it. The equivalents seem to be King Ukko the Piercer = Applejack (honest, stubborn, family stag/mare), Mustikka the Tracker = Twilight Sparkle (sharpminded, NoSocialSkills, master organizer), Skiold the Bold = Rainbow Dash (brave, loyal, impulsive), Kol the Singer = Rarity (artistic, LargeHam), Galderhorn the Sorcerer = Fluttershy (shy, soft-spoken, cares for spirits/animals) and Heikko the Humongous = Pinkie Pie (constantly happy, hedonistic, CloudCuckoolander)
* SmugSnake: Lord Eminence
* StopWorshippingMe: Luna and Celestia, especially the latter, who says she outlawed the worship of herself centuries ago in Equestria. They both reluctantly accept foreigners worshiping them, though Luna gets outright livid when she hears reindeer not only worship her and [[SuperpoweredEvilSide Nightmare Moon]] as the same entity, but used to practice [[HoldYourHippogriffs cervine]] [[HumanSacrifice sacrifice]]. Despite this, she keeps supporting the Temple of [[IHaveManyNames Hrimfaxi]] through the fic, though that seems to be for their social work in a poor nation and because of their claims that DarkIsNotEvil. [[spoiler: And maybe because she in her youth actually encouraged the forming of the cult, and feels responsible for it.]]
* SuicideByCop: [[spoiler:Twilight theorizes that Wiglek, tired of his immortality ([[AndIMustScream having been trapped under a glacier for centuries]] and all), is only supporting things like [[HumanSacrifice sacrificing sentient beings]] so that Luna will end his undead existence once and for all]].
* TalkingToTheDead: The deer of Hrimfaxi's temple can do this. They even try it to summon Wiglek's ghost to talk to him. It doesn't work. [[spoiler:Note that ghosts in this universe were scientifically proven TO exist. Then think about why this wouldn't work.]]
* TalkLikeAPirate: Mr Moccus, first mate on ''The Crimson Kraken''. He is the ''only'' pirate to speak like that, [[LampshadeHanging which Spike points out]]. He claims the Pegasi he learned Equestrian from long ago just happened to have that accent.
* TranslatorMicrobes: Twilight Sparkle knows a spell, developed using combined unicorn and zebra magics, that temporarily learns a language from a native speaker instantly. It has some minor issues: you automatically gain the "teacher's" dialect and vocabulary, and the casting process is potentially embarrassing. [[NoSocialSkills Of course]], Twilight causes misunderstandings due to the latter.
* UncannyValley: Invoked within the story. Spike finds nidhoggs disgusting because they look very similar to dragons but clearly ''aren't'' dragons.
* VillainHasAPoint: Even Twilight admits that maybe the pirate leader would be a better king than the current one who has spent much of his reign in a constant state of inebriation.
* YourCostumeNeedsWork: Spike [[ItMakesSenseInContext has to get into a place and the management would certainly let him in if they only knew he was Spike the Dragon]]. Unfortunately, there has been several people dressed like him trying to get in already, and everybody says he must be a reindeer kid in a bad dragon costume.