Trigun/Nightmare Fuel

Trigun has an incredible amount of violence, blood and horror, almost all of which is absent from the anime.

Part One

 * The Rodderik's TRUE crimes, Macekred in the anime and Dark Horse Manga., which makes their Karmic Death at Legato's hands that much more satisfying Moment of Awesome.
 * The men who attack Wolfwood in the Church. Under their masks, their mouths are sewn shut & they have screws in their eyes! Their jackets also resemble the Rodderick's...

Part Two

 * Part Two begins with the (offscreen) gang rape and death by torture of a girl who's family had a long feud with another.
 * Leonof's Villainous Breakdown. It starts with him tearing his cheek, then his Fingore when defeated. plus his cases full of human viscera,
 * Grey the Ninelives. In the anime he's indistinguishable from a robot, but in the manga, he cuts Descartes, the boomerang-throwing giant from Episode 1, in half with his own weapon. Then, when he faces Wolfwood, there's his "TRAITOR!!!" shriek. Unlike the anime version, he bleeds High-Pressure Blood & sheds tears! When his arms is severed, it crawls to the door release, so the main body can resume the battle. And it's mouth is...not right.
 * In Maximium Chapter 23, the giant Chinese-themed bandit attempts to rape a woman. "You will be my 13th wife", "The other 12 are all broken", and "You will join them in heaven now" are just a sampling of some of his creepier quotes.
 * The unnamed giant aiding Legato. It proves Not So Stoic & started flashing it's deformed mouth.
 * Raidei Rising  combined with Tear Jerker.
 * Raidei Rising  combined with Tear Jerker.

Anime

 * Legato Bluesummers. A personification of nihilism combined with the relentless drive of the Green Goblin, and telepathic powers that can make a person claw his heart out, shoot himself dead, or just turn them into puppets for him to speak through. His goal, his voice (in both Japanese and English), his theme (which sounds like a demonic stereo system), his ability to turn any potential kindness into cruelty—everything about this guy is absolutely terrifying. Only Legato can make eating sweets downright creepy.
 * Vash The Stampede himself. If you never meet him, if you're just simple townfolk who never gets to know the guy, you'd be terrified to death of a name known as The Humanoid Typhoon. Let's not forget that as good-natured as Vash can be, when he's absolutely enraged he becomes too much for anyone to handle. Don't believe me? Just ask Monev The Gale.