* JerkassWoobie: For some, Nadia.
* MagnificentBastard: A few. Lord Loss. The Kah Gash. Beranabus.
* MoralEventHorizon: Lord Loss does this in his [[EstablishingCharacterMoment very first appearance]], with [[spoiler: slaughtering Grubbs' family in a most cruel and horrific manner, and giving their bodies to his minions as toys.]]
* NauseaFuel: Some of the Gorn, and a few demon realms as well. Like that one from [[spoiler: The Board]] in ''Demon Thief''. You know the one...
* NightmareFuel: Begins just from looking at the cover of the first book, and once you actually read it...
** What stands out particularly is the ending to the book ''Bec'', where the titular protagonist/narrator gives a rather detailed description of the various demonic beings she is surrounded by while trapped in a tunnel underground, as the light fades into darkness. And then gives a very graphic description of the sensation of being eaten alive by the various creatures (with claws, teeth, beaks and tentacles), with the implication that the last thing she ever hears is the sound of her own screams in the dark.
** In another incident, a guard fires two bullets at a demon lady, who proceeds [[spoiler: to stop both bullets in mid-air, transform them into demonic butterflies, and return to sender. More specifically, [[EyeScream his eyes]], and from there, his brain. Slowly.]]
** After Juni Swan's [[ImpaledWithExtremePrejudice de]][[StalactiteSpite ath]] , she is resurrected as an AxCrazy undead....''[[HumanoidAbomination thing]].''
* TheScrappy: Nadia Moore.
* SlowlySlippingIntoEvil: Grubbs does this toward the end of the series after [[spoiler: he allows his Wolf side to surface and, in his words, "becomes a mix of a human, magician, wolf and Kah-Gash."]] These acts range from allowing Antoine Horwitzer to be slaughtered to ripping out Kernel's eyes because he refused to help with Grubbs's cause. [[spoiler: He gets better though.]]
* TearJerker: [[spoiler: Dervish]]'s death.
** Also [[spoiler: Bill-E]]'s.
** Bec confronting Dervish about simply using her to relive every moment of [[spoiler: Bill-E]]'s life.
** Kernel returning home to his parents after being missing for ''[[YearOutsideHourInside seven years]]''.
* WhatDoYouMeanItsForKids: ''The Demonata'' is quite possibly the most extraordinarily hyperviolent children's series '''ever written'''. One of the tamest examples is Grubbs throwing rats' guts on his sister while she showers, just a few pages before he comes across her and their parents' savagely murdered corpses, in a room covered with their blood. Decapitation, dismemberment, infanticide, impalement, torture, mutilation and all manner of horrible deaths occur in every book, sometimes dozens in a single scene. To say nothing of all the bullying, kidnapping, animal cruelty and all manner of sins that the ''heroes'' get up to.
* TheWoobie: Give just ''one'' moment when Kernel was actually happy (excluding the time spent with his little brother Art, [[spoiler:who turned out to be a ''demon'']]).