This game series is literally filling with horrors and we have to be careful.
''VideoGame/DiabloII'' and ''VideoGame/DiabloIII'' have [[NightmareFuel/DiabloII their]] [[NightmareFuel/DiabloIII own]] pages.
* 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.
* The [[http://www.diablowiki.net/Diablo_I_Manual#The_Darkening_of_Tristram Darkening of Tristram]] as described in the ''Librarius Ex Horadrim'' from the Diablo I Manual, particularly the vivid description of the possession of young Prince Albrecht by Diablo himself, and the horrific effects it has upon both the poor kid and the surrounding vicinity of the labyrinth.
* 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]].
** "Ah! Fresh meat!"
* 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.]]
* As does [[https://www.youtube.com/watch?v=8RRM5EW66Ac this]]. One can feel an incoming doom from the darkness.
* [[spoiler:Diablo has possessed your character.]]
* The manual tells how [[BarrierMaiden Tal]] [[SealedEvilInAPerson Rasha]], the leader of the Horadrim, sacrificed himself to contain the soulstone of Baal (which had been shattered, meaning that Baal's essence would eventually be able to escape). Tal Rasha had the shard driven into his heart, and his companions [[AndIMustScream sealed him inside a tomb to wrestle with the spirit of Baal for eternity.]]
* This poem just reeks of ParanoiaFuel:
-->I can see what you see notó
-->Vision milky, [[EyeScream then eyes rot]].
-->When you turn, they will be gone,
-->Whispering their hidden song.
-->Then you see what cannot beó
-->Shadows move where light should be.
-->Out of darkness, out of mind,
-->Cast down into the Halls of the Blind.