* AngstWhatAngst: Played with for Lauren in Season 2. After [[spoiler:Nadia dies (in Lauren's [[DiedInYourArmsTonight arms no less]]]]), Lauren spends the next episode going through a realistic process of grief. While it is gone by the next episode, this can be justified by how reserved Lauren typically is, which is implied to be the only way she survived the Fae world.
** Ultimately averted in Season 3, Lauren finally breaks down and admits how much the last years have affected her.
* AnguishedDeclarationOfLove: The bathtub scene in 3x12 with Tamsin talking to Bo could arguably count as this.
* CompleteMonster: [[MadScientist Dr. Isaac Taft]] from season 3 proves HumansAreTheRealMonsters in a show full of vicious Fae. Desiring to [[IJustWantToBeSpecial become a powerful Fae himself]], Taft has multiple Fae kidnapped and subjected to hideous and torturous experiments before dumping their corpses into a mass grave. One of the few survivors is left mentally scarred and nearly insane. Taft captures the succubus heroine Bo's ex-boyfriend Dyson and has him experimented on as well, planning to blackmail Bo's current lover Lauren into experimenting on Dyson to transport his essence into Taft. Interested only in his own advancement, Taft believed that with [[ScrewTheRulesIHaveMoney billions of dollars, he could do anything he desired]].
* DesignatedVillain: The Norn arguably. Her deal seems to be: you sacrifice that which you value the most in exchange for what it is you want. If that is the case (which Dyson apparently knew), then it's his fault for not knowing what it was that he valued the most. Her behavior after is her merely sticking to the deal, and refusing to go back. If someone had ''offered'' her something in exchange for Dyson's love, that would be different.
** They tried, and she refused. She took great pleasure in everyone's frustration and misery, and was uncaring at best about the possibility of the Fae being wiped out. Maybe not a villain, but definitely an unrepentant JerkAss.
** Hale's rejection of Kenzi in "Fae'd to Black" is portrayed as a KickTheDog moment. But he had to reason to think anything was actually wrong with her (nor did anyone else), and last time she barged in him during a meeting (ignoring his attempts to tell her to stop) to talk about fashion. It's hardly surprising that he shut her out at the end.
* EnsembleDarkhorse: Kenzi.
** Vex [[LampshadeHanging Lampshaded]] this in season 3.
* EvilIsSexy: The Morrigan.
* HellIsThatNoise: The Banshee's wail.
* FanPreferredCouple: [[LesYay Bo/Lauren or Bo/Tamsin]].
** Dyson/Kenzi is popular as well, having been subtly hinted at from season 1 and heavily teased in season 4 [[spoiler:despite Kenzi's [[BetaCouple official relationship]] with Hale as of 4x06]].
* IdiosyncraticShipNaming: Bo/Lauren=Doccubus. So called because Lauren is a [[HotScientist doctor]] and Bo is a [[HornyDevil succubus]].
** And Valkubus is Valkyrie (Tamsin) and Succubus (Bo).
* LGBTFanbase: Developed a strong one due to the positive portrayal of the bisexual heroine, and the respective way it handled Bo and Lauren's relationship.
* MagnificentBastard: Lauchlan/The Ash II.
* OT3: Unsuprising, given the love triangle, or now, love (sort of) rhombus.
** Bo/Dyson/Lauren
** Bo/Lauren/Tamsin
** There have even been a few Bo/Dyson/Kenzi fics floating around the archive
* ShipTease: Kenzi and Hale, [[spoiler:until the ship was canonized in season 4]].
** Kenzi and Dyson. Though the pairing is not officially canon, the two of them have had a few interactions that can absolutely not be classified as platonic.
* {{Squick}}: "Let the Dark Times Roll". When Bo asks to see the paperwork that claims [[spoiler:she's now Dark]], the Dark Fae records keeper ''tears off his scalp'' and gives it to her. She is appropriately grossed out.
** In "End of a Line", the only way to take control of or know who commands Revenants is to drink their blood. Eventually, Bo herself is forced to do this.
* TheyJustDidntCare: Tamsin mispronounces the worth "Kitsune" ''every time she says it'' by dropping the last syllable. Protip: The E is not silent. Though that could just be that ''she'' doesn't care.
** Though in fairness, she's also one of the only people who pronounces the "Dal" in "Dal Riata" correctly.
* WhatAnIdiot: Really, Kenzi? You're in the house of someone you know isn't human, and eat their food without checking for permission ''or'' to see what it is? That's both very rude and very stupid.
* TheWoobie: Bo has accidentally killed a lot of people, a lot of whom were her lovers, Lauren has been [[spoiler: manipulated into being a slave to people who hate humans ''twice'' and stayed with her coma-girlfriend for five years only for her to die violently before her eyes straight after she woke up, and her treatment took a turn for the worse under Lachlan]], and Kenzi's stepfather was apparently so bad that she was nearly willing to risk her worst fear ([[spoiler: Baba Yaga]]) to try and rid herself of him and she ended up on the streets from a young age. Honestly, though, [[DysfunctionJunction no one in the gang's life seems to have been a bed of roses]].
** IronWoobie: Since they all keep going. Bo says Lauren is the strongest person she's ever met. Dyson, meanwhile, calls Kenzie the strongest person.
* XMeetsY: For the UrbanFantasy and the plentiful {{Fanservice}}, the show has been described as "Series/{{Supernatural}}'s DistaffCounterpart".