History Literature / TheMortalInstruments

** Celine Herondale's suicide takes place long before the story proper, but her relationships with current characters make her important.

* NotGoodWithRejection: Really, it gets to the point where should-be TrueCompanions are abandoning each other to vampires and demons for slights like "I can't believe you like her/him more than me!" and "It wasn't my fault!" Kind of sends the underlying message that this is all teens are capable of.

* LoveMartyr: Clary, Jace and Simon could all qualify.
** Clary is devoted to Jace, despite the fact that he is a DeathSeeker and/or a positive magnet for MindControl.
** [[invoked]] Jace and Simon are devoted to Clary, despite her being a bit of a DamselScrappy. Simon in particular [[IJustWantMyBelovedToBeHappy hangs in there]] even after it is absolutely clear that Clary wants to be with Jace and he himself begins to date other (supernatural) girls.

* TheDreaded: Agramon in ''City of Ashes'' is made of this trope. Of course, he is the Greater Demon of Fear within the setting and kills people by appearing to them as their greatest terror. Gets {{narm}}tastic when he appears to Jace as [[spoiler: Clary's corpse]], despite the many, ''many'' other things that would make [[FridgeLogic more sense]] with [[FreudianExcuse Jace's]] [[AbusiveParents backstory]].

* DatingWhatDaddyHates: All over the place. Isabelle dates anybody but other Shadowhunters, intentionally bringing home boys she knows her parents would disapprove of, Jace says it's to get attention, it works - in the wrong way. Alec winds up in a gay relationship with a warlock. Jocelyn isn't wild about her daughter dating the boy [[spoiler:that Valentine raised,
though she eventually comes to accept it.]]

* DatingWhatDaddyHates: All over the place. Isabelle dates anybody but other Shadowhunters, intentionally bringing home boys she knows her parents would disapprove of, Jace says it's to get attention, it works - in the wrong way. Alec winds up in a gay relationship with a warlock. Jocelyn isn't wild about her daughter dating the boy [[spoiler:that Valentine raised]]. Jocelyn and Luke's relationship has caused them no end of grief over the years. Valentine forced Stephan Herondale to divorce Amatis simply because she was Luke's sister. Aline and Helen's lesbian relationship is controversial for Shadowhunters. Somewhat invoked and somewhat subverted when Maia and Simon date: A werewolf and a [[spoiler:vampire]] dating is controversial but their mutual surrogate father figure, Luke, doesn't care and thinks highly of both of them. Worth noting that while these relationships are all said to be taboo, actual opposition or fallout is very low-key if it's seen at all.

* CostumePorn: The series loves its lavish description of anything and everything a character wears. It only gets lavish as time goes on; at least one critic of ''City of Heavenly Fire'' complained that the book spends as much time on its plot as it does describing wardrobe.

** Played straight with [[spoiler:Jonathan/Sebastian, Clary's ''real'' brother, who unashamedly loves Clary romantically. In ''City of Glass'', he kisses her while knowing that she is his sister (she on the other hand doesn't know at the time) and in ''City of Lost Souls'' offers to make her his queen of the new world he wants to create.]]

* BeleagueredAssistant: It could be argued that Alec and Isabelle are this for Jace. While he ''is'' very talented in DemonSlaying, he is also extremely reckless and very frequently ends up as a DistressedDude. Early on it is noted that Alec has never killed a demon, despite being the oldest of their PowerTrio, mostly because his attention is focused on keeping Jace (and to a lesser extent Isabelle) from serious harm. This trope spreads, almost like a disease, when Clary enters the picture, giving her her own set (mostly Simon and Luke, although Isabelle and the others also take turns). Magnus eventually starts feeling like this for the entire group, since [[AppliedPhlebotinum his magic]] is needed by just about everyone.

** [[spoiler:Clary unintentional, as Valentine didn't know Jocelyn was pregnant when he experimented on her with angel's blood]].

* MixedAncestry: Technically anyone of note in this series. Shadowhunters are half-angel half-human, Warlocks are half-demon half-human, Faeries are half-angel half-demon, etc etc.

%% Zero Context Examples are not allowed on wiki pages and have been commented out. Please add sufficient context before uncommenting.

[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/618o7ecodrl_ac_sy400_ml3.jpg]]

** [[NotSoDifferent Many Downworlders in turn]] have a low opinion on Shadowhunters, considering them self-righteous jerkasses. Magnus seems to be the only warlock who has no visible prejudice against Shadowhunters.

* SpellBook: The Gray Book is dedicated to the [[GeometricMagic Angelic Runes]] used by Shadowhunters, and the Book of the White with spells [[TheNecromancer affecting life and death]] among other things. Shadowhunters and Warlocks are prone to collecting spell books, the former to keep them under lock and key, the latter in order to use them.

%% * {{Expy}}: Most of the characters are expies of Literature/HarryPotter characters [[AlternateCharacterInterpretation as]] [[DivergentCharacterEvolution inter]][[{{Jossed}} preted]] by Creator/CassandraClare's old fanfic The Fanfic/DracoTrilogy:

%% * {{Brainwashed}}: [[spoiler: Jonathan]] does this to [[spoiler: Jace]] in ''City of Lost Souls''.

** [[spoiler:In ''City of Fallen Angels'', after his rebirth, Jace is left vulnerable to demonic possession; his death erased the protective effects of a magic ritual all newborn Shadowhunters are given to protect them demonic possession. Lilith takes advantage of his new Achilles' heel, sending him nightmares and forcing him to do her bidding. Even after she's defeated, Jace is then forced into a corrupted form of the ''parabatai'' bond, wherein Sebastian imposes his will and beliefs onto Jace]].
** [[spoiler:Amatis Herondale in ''City of Lost Souls'', after Sebastian captures her and forces her to drink from the Infernal Cup, turning her into a Dark Shadowhunter. Also happens to the other Endarkened Shadowhunters, including the Blackthorns' father, Andrew.]].

-->"You told me you were three hundred! You're seven hundred years old?"
-->"Well, eight hundred, but I don't look it."

* GodAndSatanAreBothJerks: The greater demon Azazel, and the greater angel Raziel are summoned at different points during ''City of Lost Souls'', by the main characters, who desperately need a weapon that can break a demonic bond. The demon Azazel offered a solution at the price of being set free, which the good guys had to decline, while the Angel Raziel was extremely insulted at being summoned 'like a dog' by someone who did not carry 'The Mortal Instruments', and only gave the heroes the weapon they needed as opposed to killing the one who summoned him because the summoner, Simon, had a rune which would kill anyone who tried to hurt him.

-->'''Jace:''' There’s no such thing as vampire mojo.

* AnguishedDeclarationOfLove: Clary gets one from Simon and another from Jace, while [[spoiler:Jocelyn gets one from Luke in ''City of Glass'']]. Magnus's is more of an Irritated Declaration Of Love, when [[spoiler:Alec demands to know why he hasn't called him back]], resulting in this exchange:
-->Magnus: You're an idiot.
-->[[spoiler:Alec]]: Is ''that'' why you didn't call me? Because I'm an idiot?
-->Magnus: No. I didn't call you because I'm tired of you only wanting me around when you need something. [[AllLoveIsUnrequited I'm tired of watching you be in love with someone else]]- someone, incidentally, [[IncompatibleOrientation who will never love you back]]. Not the way I do.
-->[[spoiler:Alec]]: You ''love'' me?
-->Magnus: You stupid [[spoiler:{{Nephilim}}]]. Why else am I here? Why else would I have spent the past few weeks patching up all your moronic friends everytime they got hurt? And getting you out of every ridiculous situation you found yourself in? Not to mention helping you win a battle against Valentine. And all completely free of charge!
-->[[spoiler:Alec]]: I hadn't looked at it that way.
-->Magnus: Of course not. You never looked at it in any way. I'm seven hundred years old, [[spoiler:Alexander]]. I know when something isn't going to work. You won't even admit I exist to your parents.

* TheWildHunt: The Wild Hunt appears in ''City of Heavenly Fire'' with [[spoiler:Mark Blackthorn being forced to join them]]. They are at least partially comprised of [[TheFairFolk faeries]], are led by Gwynn ap Nudd, and collect the dead.

** In ''City of Heavenly Fire'', Clary gets one of two swords her father commissioned that was specifically meant to be an Ancestral weapon. Sebastian/Jonathan already has the other.
** There is also Cortana, the Carrstais ancestral sword. Emma inherited it from her father.

* ButNotTooForeign: A lot of these in non-white characters, though there are a couple of aversions.
** Magnus subverts this. He is first described to be the son of a Dutch father and an Indonesian mother. However, his Dutch father was merely adoptive, seeing as his real father is a Greater Demon whose real form doesn't exactly abide by human racial category, leaving Magnus to mostly take after his Indonesian mother (except for the catlike slitted pupils, which he inherited from Asmodeus).

** The Hebrew words that Valentine mutters after Clary rips apart his yacht in ''City of Ashes'' comes up again in the climax of ''City of Glass'', [[spoiler:when she writes them to transfer Raziel's allegience to her.]]

** Jace has a star-shaped mark on his shoulder [[spoiler:which is a birthmark of the Herondale family]].

* GratuitousGreek: Interestingly averted despite the regular use of GratuitousLatin and the fact that Shadowhunters are usually educated in both Classical languages. While it is mentioned that some texts, such as the Book of the White, are written in Greek, nobody seems to drop any Greek phrases to anybody that would not be expected to already know the language anyway, even though they often do so with Latin.

%% * HiddenElfVillage: Idris and the Faerie Realm.

** In ''City of Heavenly Fire'', [[spoiler:Asmodeus takes all of his memories of Clary and the Shadow World from him as part of the deal to return everybody from Edom to Earth. This is both because he relishes human memories and he knows it will hurt all of Simon's friends, especially Isabelle, to be forgotten by him. Magnus is able to restore some fragments of Simon's memories, but for the most part he has to start over from scratch]].

** ''City of Heavenly Fire'' has many new characters added that would play important roles in ''Literature/TheDarkArtifices''. The most notable, of course, is Emma Carstairs (who has about a dozen chapters dedicated to her), but there's also the Blackthorn siblings (Mark, Julian, Livia, Tiberius, Drusilla, and Octavian), Diana Wrayburn, and Malcolm Fade.

* LoveDodecahedron:
** Clary falls for Jace. [[MuggleBestFriend Long time best friend Simon]] has always loved Clary, but Clary [[ObliviousToLove doesn't find out until later]]. Alec has a crush on [[spoiler:[[HoYay Jace]]]], who doesn't find out at all. Simon has a crush on Isabelle, Alec's sister. She loathes him when they first meet but he grows on her. By the end of ''City of Bones'', Jace has fallen for Clary as well. Later, [[OurWerewolvesAreDifferent Maia]] is introduced. She likes Simon, and he likes her back. [[spoiler:[[FurAgainstFang But we can't let anything in this story be simple]]. [[OurVampiresAreDifferent Sorry Simon.]]]]. By now, [[CampGay Magnus Bane]] has been introduced. Guess who ends up with him? In ''City of Glass'', yet another player is introduced, Sebastian. Clary has a short fling with him. Only it turns out that [[spoiler:Jace and Clary ''aren't'' actually related. But in Sebastian aka Jonathan's case, it's for real. [[{{Squick}} And he knew it]]]]. Then there's Jocelyn's love history, which is simpler ([[ObliviousToLove Lucian]] / [[BigBad Valentine]]), or other side love interests like Isabelle's fling with Meliorn or Maia's ex Jordan. As of ''City of Heavenly Fire'', [[spoiler:Clary/Jace is on, Alec/Magnus is on, Simon/Isabelle is off but probably [[WistfulAmnesia not for much longer]], Jocelyn/Lucian is on, and Maia/Jordan is off ([[ShipSinking because he's dead]]), though Maia has found another love in Bat.]]

** Valentine Morgenstern. "Morgenstern" means "morning star" - signifying, of course, Lucifer.

** The City of Bones and the Spiral Labyrinth are also supposed to be this. Hence the Silent Brothers can come and go through various entrances around the world. The warlocks' great library is hidden even from the Clave, although they can apparently deliver supplies to Idris via Portal upon request.

* TheStarscream: [[spoiler:Raphael Santiago. According to Camille, he was the reason she left - he killed mundanes and blamed them on her, causing her to flee. When she did so, he seized her position and told the rest of the New York vampire clan that she was struck with wanderlust and a desire to travel (something that was not unheard of in vampires.)]]

* TokenMinority: Simon is [[NiceJewishBoy Jewish]] ([[spoiler:this is especially hard for him once he becomes a vampire]]), Maia is [[ButNotTooBlack biracial]], and Magnus had a mortal Indonesian mother.

It has far more than tripled now. In addition to ''The Mortal Instruments'' and ''The Infernal Devices'', ''Literature/TheDarkArtifices'' wrapped up its publication in 2018, ''The Last Hours'' is ongoing, and there has been talks for a new trilogy to end all (Shadowhunter) trilogies, ''The Wicked Powers''. Note that all of these are separate series within the same universe, and each trilogy (not including the double-trilogy of ''The Mortal Instruments'') is written so that it can be read on its own.

A [[FilmOfTheBook film version]] was released August 2013, with Creator/LilyCollins and Creator/JamieCampbellBower having been cast as Clary and Jace; the sequel was scheduled to start filming in 2014, [[StillbornFranchise but has since been cancelled.]]

!!The Film Adaptation provides examples of:
* AdaptationDyeJob:
** In the books both Clary Fray and her mother, Jocelyn, have green eyes. Here they have brown eyes, also their red hair is darker than described appearing almost brownish.
** Jace Wayland has golden eyes in the book, but blue eyes here.
** Simon Lewis has brown eyes in the book, but has green eyes here.
** The Lightwood siblings went from having black hair in the books, to being brunettes here. Also Isabelle’s eyes went from dark brown to blue.
** Luke Garroway has blue eyes in the books and brown eyes here.
** Emile Pangborn has grey hair in the books and black hair here.
** Samuel Blackwell is a redhead in the books but black haired here.
** Valentine Morgenstern has white-blonde hair and black eyes in the books. Here he has dark brown hair and blue eyes.
* AdaptationInducedPlothole: In the book Simon was abducted by vampires because he'd been turned into a rat, and they mistook him for one of them. In the movie, they took him as a hostage because they wanted the Mortal Cup. The movie failed to give us any possible use Vampires could have for the Cup.
* AlternativeForeignThemeSong: SCANDAL's [[https://www.youtube.com/watch?v=IfUXWr_x1Pg "Rainy"]] is the theme song for the Japanese release of the film.
* AmbiguousEnding: Because of the cancelled sequel, the movie ends [[spoiler: with no one knowing for sure where Valentine is]], whether Clary and Jace agree that [[spoiler: they're not really siblings]], when Jocelyn will wake up, or what will happen with the two other Mortal Instruments. But hey, at least [[spoiler: they got the Cup]].
* BeethovenWasAnAlienSpy: Music/JohannSebastianBach is stated to have been a Shadowhunter and wrote chords that repel demons into his music.
* BlackDudeDiesFirst: [[spoiler:Madame Dorothea, played by CCH Pounder, is the first named character to kick the bucket courtesy of DemonicPossession]].
* BombproofAppliance: Clary hides in a fridge with the door closed over while a cooker explodes right next to the fridge.
* CastFullOfPrettyBoys: The film has a ''ludicrously'' [[http://25.media.tumblr.com/tumblr_m8m16jjK3y1rdyda1o1_500.jpg attractive array of males]] in the cast - the females are pretty too, but there's much fewer of them.
* ExtendedDisarming: Madame Dorothea refuses to let Shadowhunter Jace inside her apartment armed. He drops his sword in her umbrella stand, followed by a knife. Then another sword, another knife, more knives...and ''still'' more knives. When he's "finished" and starts walking towards the door, she raises her eyebrows, points to his boot, and he removes one more large knife to add to the collection.
* FilmOfTheBook
* HeldGaze: Magnus and Alec have one when they first meet. Cue the squeals of fangirls everywhere.
--> "Him. The one with the blue eyes."
** Clary and Jace also share one of these when [[LiterallyFallingInLove Clary accidentally falls on top of him]].
* HollywoodNerd: Clary's best friend Simon is a shy, awkward, D&D-loving nerd who can't get her to notice that he's in love with her (and is eventually rejected in favor of the dashing hero Jace.) He is played by the ''gorgeous'' Creator/RobertSheehan.
* HollywoodOld: 36-year-old Luke Garroway is played by 29-year-old Aidan Turner.
* InTheHood:
** Jace dons a few hoods while investigating Clary.
** Magnus Bane wears a hooded long coat when he sneaks in the Institute to heal a mortally injured Alec Lightwood.
%% ** Clothing of choice of all the Silent Brothers.
* ITakeOffenseToThatLastOne: Simon confronts Clary about her decision to associate with Jace when Jace steps out of the room:
--> '''Simon:''' *whispering* Your mom is [[spoiler: ''gone'']], and you're hanging out with some dyed-blond-wanna-be-goth-wierdo?
--> ...
--> '''Jace:''' *re-entering room with a phone* You need to check this. Oh, and for the record, my hair is naturally blond.
* MustacheVandalism: Plus some horns, to a photo of Jace. Somebody was really jealous...
%% * OrangeBlueContrast: The 2013 [[http://www.imdb.com/media/rm1227610624/tt1538403 movie poster]].

* WeddingDay: ''City of Heavenly Fire'' closes with [[spoiler:Jocelyn and Luke's wedding in Upstate New York.]]

* GratuitousGreek:
** Interestingly averted despite the regular use of GratuitousLatin and the fact that Shadowhunters are usually educated in both Classical languages. While it is mentioned that some texts, such as the Book of the White, are written in Greek, nobody seems to drop any Greek phrases to anybody that would not be expected to already know the language anyway, even though they often do so with Latin.
** Though the series do dabble in this a few times. At the end of ''City of Lost Souls'', Sebastian's message for the Clave is ''erkhomai'' -- "I am coming".

There is also a television series entitled ''Series/{{Shadowhunters}}''. The first episode was aired in January, 2016.

** In ''City of Heavenly Fire'', Clary gets one of two swords her father commissioned that was specifically meant to be an Ancestral weapon. Sebastian/Jonathan already has the other. Emma's Cortana also counts.

* AnimalEyes:
** Magnus Bane has greenish-yellow eyes with vertically-slit pupils, like a cat.
** In humanoid form Asmodeus has catlike eyes.

** In ''City of Heavenly Fire'', Clary dreams of a rune several times and describes it as "a shape like two wings joined by a single bar".

* TheBeautifulElite: All the Nephilim are somehow good-looking (with the possible exception of Hodge and [[spoiler: The REAL Sebastian Verlac]]). The vampires, too.

* BigApplesauce: The first two books, as well as the fourth. The third book is set in Idris, but the trope is still in play, as the representatives of the faeries, vampires, warlocks and werewolves that come to Idris (which is located between France and Germany) are all from New York City. The prequel trilogy is set in VictorianLondon.

* BioAugmentation: [[spoiler:Valentine unknowingly added angel's blood to Clary before she was born. He also added angel's blood to Jace before he was born, through the naivete of his birth mother Celine Herondale]].

** Thanks to the demon blood, [[spoiler:Sebastian[=/=]Jonathan]] had these at birth. Jocelyn was so repulsed by him she refused to care for him.
** [[spoiler:Amatis Herondale when under the influence of the Infernal Cup]].

** There's also the protagonist Tessa Gray who is a Warlock (part [[{{Nephilim}} Shadowhunter]] and a Eidolon Demon).
** Jonathan Morgenstern is a shadowhunter, who is also largely demonic through [[BigBad Valentine's]] experiments. Lilith even claimed that she sees him as her own child, for she has given her blood to Valentin to make Jonathan the one he has become.

** [[spoiler:Amatis Herondale in ''City of Lost Souls'', after Sebastian captures her and forces her to drink from the Infernal Cup, turning her into a Dark Shadowhunter]].

** Clary Fray is often almost insanely self-absorbed. Even though she is unconcerned about things like popularity, she can be rather spectacularly heedless of other people's feelings, tends to jump into dangerous situations without thinking about it and will do whatever she wants even if it literally results in endangering the entire world. Luke calls her out on it one time, [[spoiler:when she tries to blindly Portal to Idris]] and she is shocked because he has never chastised her before.

** In ''City of Bones'' [[spoiler:a fortune teller tells Jace that he will "Love the wrong person". He falls in love with Clary, who turns out to be his sister.]]
** [[spoiler:Subverted.They end up not related.]] Jace [[spoiler:is the son of his supposed Father's second second-in-command.]] And Clary [[spoiler:ends up with Jace, though only after meeting and kissing a boy she finds out is her REAL brother. Oops.]]
** In ''City Of Lost Souls'' [[spoiler:Sebastian/Jonathan is shown to actually want Clary, backing her up against a wall and forcefully kissing her, while going on about how they can be evil and rule the world together.]]
* ButNotTooForeign: Every character of a different ethnicity who appears in the series always turns out to be biracial, (usually half Caucasian). Magnus is half Indonesian/half demon, Aline is half Japanese[=/=]half Caucasian, Maia is half black[=/=]half Caucasian. See a trend here?

%% * CanNotTellALie: The fairies. This should not be mistaken to mean that they are always honest.

* CommonCrossover: This series and ''Literature/TheInfernalDevices'' don't have a huge crossover file yet, but it's steadily building. Considering the fact that ''The Infernal Devices'' is really just a prequel and many characters are either ancestors of characters here or present in both series (such as Magnus Bane and various vampires), it's not surprising.
* ContemptibleCover: The first book, as seen on the page picture. Jace doesn't [[ShirtlessScene go shirtless]] at all in the first book, and hardly ever throughout the whole series. A more accurate cover artwork would probably [[http://www.impawards.com/2013/posters/mortal_instruments_city_of_bones.jpg look something like this, the teaser poster for the film adaptation.]]

* DeathSeeker:
** Jace is explicitly described as being this. Isabelle flat-out says that Jace is "in love with the idea of dying" and she and her brother Alec put considerable effort into saving him from his own recklessness.

** Like her brother, Isabelle Lightwood is not very fond of Clary at first. Later, though, she begins to open up to her.

* DemonLordsAndArchDevils: [[{{Satan}} Lucifer]], Azazel, Samael, Asmodeus, Myth/{{Lilith}} and many others. At least some are [[FallenAngel fallen angels]]. Asmodeus in particular is one of the nine most powerful, and subordinate only to [[{{Satan}} Lucifer]].

** Jace Wayland has a star-shaped mark on his shoulder [[spoiler:which is a birthmark of the Herondale family]].

* EmotionalMaturityIsPhysicalMaturity: True up to a point with warlocks. Most of them stop visibly aging when they reach adulthood, and they do not become elderly people in young bodies usually. Magnus in particular somewhat consciously tries to act the age he looks. But he also states that older warlocks do start to become emotionally detached. Fairies and vampires are more variable though. For example, Raphael Santiago looks about 14 or 15, but acts much older, which he is. Aside from FantasticRacism, most people tend to interact as peers despite real age differences. Arrogant Clave members think nothing of acting older and wiser than Downworlders that are many times their age. A romantic relationship between Alec (18) and Magnus (400+), is not seem as problematic except for the MayflyDecemberRomance issue [[spoiler: and Alec's later jealousy over the sheer number of past lovers Magnus has had]].

** Raphael Santiago discriminates against anyone who isn't a vampire.

** The vampires and werewolves do not get on well; this is because the two demon species which originally infected humans, giving rise to the vampires and werewolves, were rivaling species who hated one another.
** In ''City of Ashes'', werewolf Maia Roberts dislikes [[spoiler:Simon]] at first. ''Very'' much. [[spoiler:Until they both end up being captured by Valentine]].

* GratuitousGreek: Interestingly averted despite the regular use of GratuitousLatin and the fact that Shadowhunters are usually educated in both Classical languages. While it is mentioned that some texts, such as the Book of the White, are written in Greek, nobody seems to drop any Greek phrases to anybody that would not be expected to already know the language anyway, even though they often do so with Latin.

* HalfHumanHybrid: Warlocks are the progeny of couplings between humans and demons. They are themselves generally infertile.

* HookedUpAfterwards: [[spoiler:Luke Garroway and Jocelyn Fray]] at the end of ''City of Glass''. They planned to get married in ''City of Fallen Angels'' but the marriage was postponed indefinitely, with [[spoiler:Jace's possession by Lilith and subsequent disappearance]].

She usually grabs the IdiotBall and runs with it whenever Jace is involved, [[spoiler:like when possessed!Jace is able to trick her into mind-control just by batting his eyelashes at her and playing on her hormones]].
** Jace grabs it with a bloody deathgrip when he refuses to tell anyone about the possible [[spoiler:prophetic dreams he's having about murdering Clary until it's almost too late, nearly starves himself to death, doesn't sleep... oh, and ends up getting himself possessed by Sebastian. What an IDIOT.]]

* IdiosyncraticEpisodeNaming: All of the books in the series are called "City of X". The titular ''City of Bones'' is the Silent City, while the titular ''City of Glass'' is Alicante.

* InformedAttribute: The ''parabatai'' bond. Although it supposedly makes two Nephilim "closer than brothers", Alec and Jace usually seem to have little or no ability to read each other. Alec often fails to get when Jace is being sarcastic (despite the fact that Jace is almost ''always'' sarcastic). Jace had no idea that Alec was just pretending to side with the Inquisitor in order to keep her from suspecting that he intended to help Jace. Despite the alleged combat advantages of the bond, they do not really seem any more effective when fighting together than they do with others, such as Isabelle. Cassandra appears to have noticed this problem and plays up the bond considerably in ''City of Heavenly Fire'' as compared to the earlier books.
* InterspeciesRomance: Played straight with [[spoiler:Magnus and Alec]]. No [[CampGay pun]] [[StraightGay intended]]. Every witch and warlock is the offspring of a human and a demon (though Word of says that most of these cases are rape, not romance), in ''City of Ashes'' Isabelle is dating a faerie knight. The fey themselves are the offspring of demons and angels. Jocelyn and Luke and [[spoiler:Isabelle and Simon, as of ''City of Lost Souls'']], are in the same vein as Tonks and Lupin from ''Literature/HarryPotter'', with their lycanthropy and vampirism respectively being more like diseases than a genetic trait, though there are born werewolves in-universe. Helen and Mark Blackthorn are half-fey as well.

* LastEpisodeNewCharacter: ''City of Heavenly Fire'' introduces Emma Carstairs, hero of the upcoming sequel trilogy, ''The Dark Artifices''.

[[spoiler:Jace and Clary end up being siblings... though not before they've fallen in love with each other. Oops...]]\\
\\
[[spoiler:Once you get to ''City of Glass'', you find out that Jace and Clary ''aren't'' related, and that Clary's actual brother is Sebastian]].

* LoveDodecahedron: Clary falls for Jace. [[MuggleBestFriend Long time best friend Simon]] has always loved Clary, but Clary [[ObliviousToLove doesn't find out until later]]. Alec has a crush on [[spoiler:[[HoYay Jace]]]], who doesn't find out at all. Simon has a crush on Isabelle, Alec's sister. She loathes him when they first meet but he [[JustFriends grows on her]]. By the end of ''City of Bones'', Jace has fallen for Clary as well. Later, [[OurWerewolvesAreDifferent Maia]] is introduced. She likes Simon, and he likes her back. [[spoiler:[[FurAgainstFang But we can't let anything in this story be simple]]. [[OurVampiresAreDifferent Sorry Simon.]]]]. By now, [[CampGay Magnus Bane]] has been introduced. Guess who ends up with him? In ''City of Glass'', yet another player is introduced, Sebastian. Clary has a short fling with him. Only it turns out that [[spoiler:Jace and Clary ''aren't'' actually related. But in Sebastian aka Jonathan's case, it's for real. [[{{Squick}} And he knew it]]]]. Then there's Jocelyn's love history, which is simpler ([[ObliviousToLove Lucian]] / [[BigBad Valentine]]), or other side love interests like Isabelle's fling with Meliorn or Maia's ex Jordan. As of ''City of Lost Souls'', [[spoiler:Clary/Jace is on with difficulties, Alec/Magnus is off, Jocelyn/Lucian is on, and Maia/Jordan is on]].

* MacGuffin: The titular Mortal Instruments: A cup, a sword, and a mirror

* MayflyDecemberRomance: [[spoiler:Alec Lightwood is eighteen and dating Magnus Bane is around 400 years old. The fact the Magnus is an immortal warlock while Alec is human becomes a plot point in ''City of Fallen Angels'']].

** Raphael Santiago to Camille Belcourt.

* OnlySaneMan:
** Simon Lewis. Recognized that loving Clary was a dead end, and had enough self-respect to let her go and move on to [[spoiler:Isabelle and Maia]].

** Raphael Santiago is in some cases an even better example than Isabelle, but it's played with as while he's certainly proud and he does ''see'' himself and vampires as elite, the magical world (re:the Clave) does not see them as so.

*** [[spoiler:Camille was working for Lilith the entire time]].

* ShipTease:
** In ''City of Glass'', Sebastian Verlac has some sexual tension with Clary and Isabelle, which goes nowhere.

* TheStarscream:
** [[spoiler:Raphael Santiago. According to Camille, he was the reason she left - he killed mundanes and blamed them on her, causing her to flee. When she did so, he seized her position and told the rest of the New York vampire clan that she was struck with wanderlust and a desire to travel (something that was not unheard of in vampires.)]]

* SufficientlyAnalyzedMagic: The Spiral Labyrinth is a hidden library and research facility where warlocks with a scholarly bent study and experiment with both existing spells as well as developing new ones. They also accept commissions (such as from the Clave) to develop specific magic as needed. The Silent Brothers do similar work in the City of Bones, but are more narrowly-focused since they must work within the bounds of the runic knowledge granted to the Nephilim by the Angel Raziel.

** Jace is [[spoiler: supposedly the son of Michael Wayland. But then it turns out that Michael was murdered and the man who supposedly fathered him was really Valentine Morgenstern, leading to a BrotherSisterIncest problem with Clary. It later turns out that his actual biological father was Valentine's right-hand man Stephen Herondale]]. Needless to say, Jace goes through a great many surname changes, although he often uses Lightwood after his adoptive parents and siblings. [[spoiler: Worth noting that Stephen had previously been married to Luke's sister]]

* TeensAreShort: It is called out repeatedly that the main characters whose biological parents are still running around look very much like their parents, only shorter.

* TokenMinority: Simon is [[NiceJewishBoy Jewish]] ([[spoiler:this is especially hard for him once he becomes a vampire]]), Maia is [[ButNotTooBlack biracial]], and Magnus is part Indonesian.

It has far more than tripled now. In addition to ''The Mortal Instruments'' and the ''The Infernal Devices'', there are three new trilogies in the works; ''The Dark Artifices'', ''The Last Hours'' and ''The Wicked Powers''. Note that all of these are separate series within the same universe, and each trilogy (not including the double-trilogy of ''The Mortal Instruments'') is written so that it can be read on its own.

* TwoPartTrilogy: ''City of Fallen Angels'' was originally supposed to be a one-shot [[ComicBookAdaptation Graphic Novel]] follow-up to the original trilogy, until Creator/CassandraClare decided to make it the start of a second trilogy.

* YouKillItYouBoughtIt:
** In ''City of Lost Souls'', [[spoiler:Maureen Brown becomes leader of the New York vampire clan after killing Camille Belcourt]].