This game series is literally filling with horrors and we have to be careful.
VideoGame/DiabloIII has [[NightmareFuel/DiabloIII its own page]].
!!The First Game
* Sure the creepy dark seems pretty standard dungeon-crawler fare, but when you start reading into the lore of the world, and asking about some of the quests...
* The Zakarum Cathedral of Tristram, dark and endless and full of all kinds of monstrosities.
* Special mention goes to "The Butcher", a huge, fat demon who makes his residence in Tristram's church. In a room completely filled wall-to-wall with corpses [[BeefGate somewhere above the first floor]]. He killed a fairly large regiment of soldiers by himself, and [[NintendoHard he'll probably kill you without a problem, too]].
* Of course there's [[spoiler:the ending too]], although in particular when you [[spoiler:defeat Diablo as a Rogue. Her scream in the final FMV sequence is nothing short of genuinely chilling]].
* [[http://www.youtube.com/watch?v=k9pqRt38ms0 This soundtrack.]]
* [[spoiler:Diablo has possessed your character.]]
!! The Second Game
* [[DoomedHometown Tristram]], Holy crap! This village's people thought that the terror was over [[spoiler:only for TheLegionsOfHell to come pouring out of the fallen Zakarum cathedral and raze the place. They've set up shop in the burning remains of the town, turning the blacksmith Griswold into a demon, killing Wirt, and imprisoning and torturing Deckard Cain]].
* After the events of the first game, we see The Warrior [[spoiler: who was then possessed by [[BigBad Diablo]]]] in a tavern with lots and lots of people. These people were drinking heavily until these people did some bad thing to The Warrior and that prompts him to unleash the LegionsOfHell on that tavern and thus killing every single man except for Marius.
* Going to the Rogue Monastery and facing a tonload of succubi is just plain wrong and horrible. [[spoiler: Even worse if you face the Maiden of Anguish herself]]. Heaven have mercy!
** Those aren't succubi. They're what happens to Rogues who get corrupted by Andariel, including [[spoiler:Blood Raven, the original Rogue from the first ''Diablo'']]. And the Rogues that ''didn't'' fall to her corruption? You can see their bloody and often naked corpses on stakes and various implements of torture scattered all about the place. Try not to think too hard about [[ColdBloodedTorture what these poor women went through]] at the hands of the demons before they died.
* Tal Rasha. [[HeroicSacrifice Sacrificing himself]] just to help the Horadrim and [[BigGood Tyrael]] seal [[BigBad Baal]] inside a tomb for good. Imagine fighting an extremely powerful demon inside of you just reeks off fear.
* And then we go to the Cathedral of Light [[spoiler: now known as the Durance of Hate. You go all the way into a place full of [[DemonicPossession demonically possessed people]] (and demons as well). Think of it as a cursed place. To be precise, a church of evil.]]
* The gathering of the [[BigBadDuumvirate Three Prime Evils]], so horrifying that would [[SanitySlippage shatter ones' sanity]] at the sight of it. And that is just the tip of the iceberg as for the meantime, [[spoiler: Prince Aidan's [[BodyHorror transformation from a human into Diablo itself]].]]