As nightmare-inducing as ''VisualNovel/FateStayNight'' [[NightmareFuel/FateStayNight is]], there are '''reasons''' why ''LightNovel/FateZero'' is considered DarkerAndEdgier--and considering [[Creator/GenUrobuchi the writer]], DarkerAndEdgier indeed.

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* Joy to the world, the anime adaption gives us a [[SarcasmMode very nice]] animated look at what Zouken put [[TheWoobie Sakura]] [[BreakTheCutie through when she was a child]]. It's absolutely, utterly horrifying and [[NauseaFuel disgusting]]. If you don't have a fear of bugs and (specifically) worms, you will after this scene. Zouken, [[MoralEventHorizon you will burn in hell for this]]...
* Again from the anime, Ryunosuke Uryu and Caster's introduction is full of nightmare-inducing images. It doesn't help that both of them are immoral and insane.
* Sola torturing Kayneth might not be as extreme as all the other examples mentioned here, but boy is it both creepy and nightmarish.
** Probably because there are no {{Eldritch Abomination}}s, serial killers, or other supernatural aspects, just a paralyzed man who's lost his reason for existence (his magic) being emotionally manipulated--and then, when it doesn't work, physically mutilated with the threat of being reduced to a limbless husk--by the one person he cares for.
* Oh, and Caster's lab. Oh gods, Caster's lab. Think Kirei's basement from ''VisualNovel/FateStayNight'', just with a lot more blood and a lot less purpose. It consists of ''the still alive bodies of men, women, and children carved up and turned into instruments, artwork, and furniture.''
* Episode 10 has a very SlasherMovie feel. Ryunosuke being the villain and Rin being the focus character. It has a very AdultFear theme to it. Children go missing and then Rin decides to look for them ''in another city''. She sees Ryunosuke mindcontrolling kids and leading them away by the hand. Then she finds his lair. Then it's a CrowningMomentOfAwesome for Rin. [[spoiler: Then Rin nearly gets jumped by one of Caster's tentacle abominations, and Kariya gets to pull an [[CrowningMomentOfAwesome awesome]] BigDamnHeroes moment.]]
* Just Berserker possessing a [=JASDF=] [=F-15J=] with the pilot still inside. Also includes said destruction at the hands of Lancer.
** Caster's monster eating one of the planes with the pilot still in it.
--> '''Command''': "Report, what do you see? Report!"
--> '''Pilot''': [[EyesDoNotBelongThere "Eyes. So many eyes."]]
* Episode 16: There's something extremely unsettling about watching [[spoiler: Lancer's complete meltdown as he dies with his honor completely crushed, raving madly at everyone present]].
** [[spoiler: Those orange eyes pouring blood... There's nothing worse (or sadder) than seeing Lancer cursing the world with that expression...]]
** [[spoiler: It's also very unsettling that Lancer's voice suddenly turned so fittingly dark and terrifying. Creator/HikaruMidorikawa may have played some terrifying villains, but none of their voices in their worst came close with how he did Lancer's last moments in how terrifying it is.]]
** [[spoiler: Kayneth begging for a Mercy Kill soon later]]
* Episode 17: [[spoiler: Kirei's betrayal and his murdering of Tokiomi. [[SlasherSmile The rather gleeful smile]] Kirei has before stabbing him is especially unnerving]].
* Episode 18: Kiritsugu witnessed a horrific event during his childhood. [[spoiler: His PrecociousCrush transforming into a zombie and then setting off a ZombieApocalypse. He has a front row seat for people getting eaten. The Church's executors show up and kill the zombies, followed by the Mage's Association setting everything on fire. Finally, he finds out that all of this was caused by his own father, and that his father couldn't care less about any of it.]]
* Episode 21: Kariya [[spoiler: strangling of Aoi is played in a disturbingly sexual way, and Kariya's wailing once he realises what he's done is haunting.]]
* Episode 22: First, it is extremely unsettling to see [[spoiler:Kirei [[IncrediblyLamePun snap]] at Irisviel because he can't stand an ArtificialHuman with genuine feelings, when he, a genuine human, can't feel real emotions...]]
** [[spoiler: Then... your emotions are jarred between incomprehension with mild horror as "Irisviel" watches herself and a cluster of Einzbern homonculi piled up on top of each other, then feeling yourself go [[TearJerker "D'aww" over Ilya making a horrible nightmare of what might await her]] since [[HiveMind Einzbern homonculi designed for the Grail War share a common consciousness]]... then further horror as this scene falls to black ashes, meaning Irisviel's mind is literally falling apart, before revealing once more the pile of clones all staring towards the screen with a broken and empty look... before [[TheCorruption Angra Mainyu]] takes over one and [[SlasherSmile thoroughly corrupts it in a twisted, horrifying smile.]] ]]
*** [[spoiler: And then, Irisviel having a full [[PaintItBlack black makeup]] EvilMakeOver and coming to a [[HeelRealization realization]] that... not only is she dead and "something" has taken over her mind, but if she is inside the Grail, then it means... [[TheEndOfTheWorldAsWeKnowIt the end is near]].]]
*** This actually feels like a ShoutOut to ''that scene'' in Episode 23 of ''Anime/NeonGenesisEvangelion'', only done better. Much "better", for very scary values of "better", since they actually made Irisviel completely out of the UncannyValley.
*** Actually if you look closely at a shot after that you'll notice [[spoiler:all of the clones are smiling!]]
* Irisviel's [[spoiler: Angra Mainyu's]] scream of terror as [[spoiler: Kiritsugu rejects the Grail by shooting the apparition of his own daughter in the head]]. AdultFear indeed.
* Both of Kiritsugu's background episodes are filled with this. The Dead Apostles, the bees...
* Every time ''[[https://youtu.be/HUXmjBI1euA?t=1h48m54s The Dream Fades Before Dawn #3]]'' begins to play. While the first half is identical to the first iteration of the song, the second half quickly descends into creepy ambience and sounds, culminating with [[OminousMusicBoxTune an off-key, twisted, and haunting version]] of the [[DarkReprise main melody of "Let the Stars Fall Down" and "Manten"]]. Considering that this plays when [[spoiler: Irisviel falls into the corrupted Grail and Kiritsugu is shown [[KillEmAll just how his wish will be granted]]]], it can be said that the song serves as the theme of [[spoiler: [[UltimateEvil Angra]] [[TheCorruption Mainyu]]]].
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