* AlternativeCharacterInterpretation: The first book deliberately aims for this by making sure that every time [[VillainProtagonist Artemis]] does the right thing, he can explain it away as PragmaticVillainy. The psychiatrist who narrates the book argues that Artemis is a sociopath (though admittedly not a standard case by any sense of the imagination), and warns of the tendency to view him as more noble than he really is. Later books make him more of a hero, though.
** Him becoming a hero is explicitly stated to be character development. In the Eternity Code, [[spoiler:just before the mind wipe, he says that he might become the monster seen at the start of the series.]] The next book reveals that [[spoiler:he was right]].
* {{Anvilicious}}: Book 6: Go green, and you'll save the krakens, stop [[spoiler: poisoning fairies with Spelltrophy]], and keep the world from dying. Plus, Artemis Sr. puts emission filters on every vehicle they own, including the jet and helicopter. Though the series has dropped environmental anvils all over the place since its beginning.
* AssPull: Eoin loves this trope or owes it money. Technology of the series doesn't appear to have any consistency: numerous vital plot points happened just because fairy technology happens to be capable to do something we weren't informed of or has a limitation never brought up before.
** One short story in the companion book is set in the period between the first and the second book, aka when Artemis was still a egoistic criminal mastermind and Mulch was believed to be dead by the LEP. Holly goes to stop Mulch in his tracks, but she isn't supposed to know Mulch is even alive... Well, let's make him wear a mask! Voice? Did we mention all the dwarves' voices are exactly the same and even the dwarves themselves can't tell one from another? Because now they are.
** Dwarf biology can generally be relied upon to produce one new secret trump card for Mulch to get out of trouble with per book.
** Magic has a bunch of new rules too: Grease is toxic for people with magic in them, animals can get glands extracted to enhance power, runes only need one spark to do something powerful wizards can't and mesmerizing on the fair folk works except when it doesn't.
%%% What, exactly, is taking hold and what how is it doing so?
* CompleteMonster: [[OverarchingVillain Opal Koboi]] became [[CorruptCorporateExecutive head of her father's company]] by driving him insane. Organizing the Goblin rebellion alongside Briar Cudgeon, Opal took advantage of their violent nature to cause a violent uprising, planning to betray them all along. To escape prison after being arrested, Opal creates a clone, not caring it will die easily and cannot think for itself, allowing her to manipulate it. Killing [[spoiler:Julius Root]], Opal frames the innocent Holly and {{Mind Rape}}s a kind-hearted humanitarian, forcing him to send a probe into the Earth and reveal the Faerie people, hoping to cause a war behind humans and Faeries. Opal is also [[MadScientist revealed to have experimented on]] and killed endangered animals to make herself more powerful. In the final book, Opal murders her own past version of herself when the past version of her was trying to free the present Opal from prison, which causes all products produced by her company to explode, with planes crashing and global communications cutting off. Manipulating the ghosts of dead Faeries to KillAllHumans and take over the surface world, Opal shows time and time again what a heartless creature she is.
%%* CreepyAwesome: Artemis.
* DieForOurShip: Depending on whether you ship Hartemis or Artemin, either Minerva Paradizo or Holly.
* EnsembleDarkhorse: Trouble has become quite popular, thanks in part to his HeroOfAnotherStory status and rampant badassery.
** Unix of ''The Atlantis Complex'' also has a small following.
* FanPreferredCouple: Artemis/Holly is by far the biggest ship in the fandom, even [[FoeYay back when they hated each other]]. The fact that Colfer [[ShipTease keeps teasing it]] despite claiming [[ShipSinking nothing will ever happen]] doesn't help. [[spoiler:The series ends without it being [[UnresolvedSexualTension strictly sunk]] ''[[UnresolvedSexualTension or]]'' [[UnresolvedSexualTension canonized]], so he apparently decided to let fans believe what they wanted about it.]]
* GeniusBonus: The cryptography puzzles along the bottom of each book (and [[HiddenInPlainSight on the book covers]]) are more of a [[MarathonBoss Patience Bonus]], but there are little references throughout the book that just make it ''so'' much more fun if you happen to know them, or [[LateToThePunchline realize what they meant three years later]].
* {{Homage}} The ending to The Eternity Code is suspiciously similar to that of ''VideoGame/DeadToRights'', which came out a year earlier.
* IdiotPlot: The entire berserker threat would never have occurred if they had simply killed the future Opal BEFORE they put her in the reactor tank.
** It is admittedly implied to be a result of fairy society being based off of [[ActualPacifist Actual Pacifism]], so that they are neither legally allowed nor morally inclined to shoot a prisoner. Although that explanation doesn't make much sense given Artemis and Butler were also present and seemingly neither of them even thought of it.
*** They were present in the control room in Haven, not the cell block in Atlantis. They could suggest it but not do it. They probably did think of it but knew there was no point saying anything.
** The Atlantis Complex: For starter said complex is pretty much how you glue the IdiotBall on Artemis, the elven space project being accessible by a prison guard (and existing)and no one but Turnbull and the old fairy in Vietnam knowing about the magic spark trick.
* InferredHolocaust: In The Last Guardian, [[spoiler: a good chunk of technology, both human and fairy, ceases to function. This leads to chaos on both ends, but the humans bare the brunt of it as cities darken, people loot, medical equipment is useless, and '''airplanes fall from the sky'''. [[NoEndorHolocaust Nobody particularly dwells on this,]] [[ValuesDissonance and the narrator considers this a good thing.]]]]
** [[spoiler: Not to mention all of the people in cities who will starve to death because they can't get food shipped in, submariners who are trapped in steel tombs miles beneath the waves, miners stuck in shafts with no way out, and anybody on a boat, who will be most likely stranded in the middle of the ocean. The book also stated that anything connected to Opal Koboi, '''exploded''', which includes most of our modern technology, such as pacemakers. [[SarcasmMode But hey, at least people aren't distracted by TV anymore!]]]]
** Justified: [[spoiler: the narrator ends up being Holly Short, a fairy, so it makes sense as to how she wouldn't dwell on the human deaths.]]
%%* MagnificentBastard: Artemis and Opal have their moments. When they're not Smug Snakes, they're this.
* MisAimedFandom: Early in, Holly Short has a CharacterFilibuster denouncing sewage treatment as a [[GaiasLament horrible violation of Mother Earth]], inspiring FridgeHorror in readers familiar with modern Germ Theory. However, the filibuster wasn't something the reader was supposed to agree with but rather a demonstration of BlueAndOrangeMorality. The fact that elves think putting your restroom indoors is unhygienic was supposed to reinforce this.
* RunningGag: Someone asks an antagonist if their goal is "world domination" in each of the first three books only to be told otherwise.
* TheScrappy: Ark and Minerva. The latter had a huge fan outcry, due to being seen as [[ReplacementFlatCharacter a retread of Artemis pre-character development]], except just as smart as him and without the redeeming qualities.
%%* TooCoolToLive: [[spoiler:Julius, Raine]].
%%* UglyCute: Nº1.
* UnintentionallyUnsympathetic: Turnbull got a CryForTheDevil before dying with his loved one but the guy has the highest bodycount after Opal, brainwash people and was first introduced torturing an officer for another petty scheme. Only reason why Artemis would say he can't see him as a villain is because he is unaware of most of it because he was too busy guilt-tripping. Even his relationship with his loved one isn't that great when you keep in mind he brainwashed her into staying with him forever.
* TheUntwist: In the first chapter of ''The Last Guardian'', [[spoiler:Dr Argon ominously wonders if it is really possible that Artemis has been cured of the Atlantis Complex in record time. He has, and the only thing we hear of the Complex for the rest of the book are a few fleeting mentions.]]
** [[spoiler:Though it does seem to have badly damaged his self-confidance.]]
* ValuesResonance: Despite being said in his time as a mob boss, Artemis Fowl Sr's line about buying gold as a reliable investment and keeping it safe seems far more resonant in modern times.
%%* TheWoobie: Nº1.