* Kallen’s [[spoiler:{{Superpowered Evil Side}}’s utter destruction of several guild members of Iron Star]].
* Whatever Marianne did to Iron Star, because it certainly could not have been pleasant for her to say that "they probably wish they were dead" with the way she left them and then tells Kallen she’d be better off not knowing the details.
* The vast majority of the Unistrad arc considering it's ''meant'' to be Manga/FairyTail meets the horror genre. To wit:
** The first two chapters give amazing buildup with tension so taut, you can cut it with a knife. One reader even thanked the author for their nightmares.
** Chapter 41 ends with [[spoiler:Mirajane going BrainwashedAndCrazy]].
** Chapter 42 has [[spoiler:Kallen being transformed ''by'' Mirajane while she's still BrainwashedAndCrazy]].
* Kallen's brutal shredding of [[spoiler:Hoteye]] is this on several levels. For one, it shows how powerful Kallen is that her demon form was able to take down a member of Oracion Seis, [[StrongAsTheyNeedToBe all of whom were given a power boost in this fic]]. Second, it speaks of [[TheAce Nonette's]] ability as she is, insofar, the only character to actually put Kallen ''down'' when she's going ballistic. Thirdly, the shredding itself is terrifying. Kallen could've easily committed murder, like the first time her SuperpoweredEvilSide got out.
* Kalina's magic in general is a bit of this if you have a vivid enough imagination. The things she summon sound like they were designed by Creator/HPLovecraft.
* Our first [[FinalBossPreview sneak preview]] at Zero has him taking down the members of Oracion Seis in record time in a flashback when they tried to rebel against him.
* The BigBad of the Sindel arc [[spoiler:the titular character herself]] ''does not fuck around''. What does [[spoiler:she]] do immediately after getting released? [[CurbStompBattle Curb stomp]] ''[[WalkingWasteland Gildarts!]]'' Yeah, pick a god and pray, Fairy Tail [[AuthorsSavingThrow only one of them can save you now]].
* [[AssholeVictim Even if he deserved it]] [[spoiler:Ivan Dreyar's ultimate fate is to be turned into a tree by Nessa. [[NoKillLikeOverkill She then shreds the tree to pieces and then burns the remains]]. What's worse is that [[AndIMustScream Ivan can feel every moment of becoming and being destroyed as a tree]]]].
* Kalina's ultimate nightmare, Hypnox. First off, it's half the size of Domus Flau and it took down [[spoiler:Miala and Nippy]], who are capable of handling Devil Slayers. Also, this is her strongest nightmare and a significant weaker one was able to put down all of Team Quatro Cerberus without much effort. ''Think about that for a minute''.
** It's gotten worse. Hypnox was able to take on Tianzi and Nivea at the same time [[spoiler:and win]].
* [[SilentAntagonist Nirix]]. Much like [[spoiler:Sindel]], Nirix is truly a worthy ArcVillain as he has begun his rampage by taking out Kallen, Rogue, and Sting in record time.
* [[NoNonsenseNemesis Mordred]]. Everything about the guy is outright terrifying. He's [[spoiler:Lelouch [[TheUnfettered all out of fucks to give]]]] and shows exactly what happens when [[spoiler:[[PayEvilUntoEvil Lelouch]]]] [[MoralEventHorizon loses all sense of morals]] and just [[IDidWhatIHadToDo does what he feels is necessary]] [[WellIntentionedExtremist for the greater good]].