* Hishigi. Between his TranquilFury, his [[TheCynic cynical]] and [[StrawNihilist nihilistic approach to reality]], his [[UncannyValley experiments]] and [[EyesDoNotBelongThere the Devil Eyes implanted in the left side of his body]], he qualifies as [[NightmareFuelStationAttendant walking Nightmare Fuel]].
** Just after Kyo's fight with Nobunaga, when Kyoshiro has taken over Kyo's body, Hishigi shows up to stop Kyo from attacking. He laments that their deaths will not be painless because they have caught him without his sword, and his expression is ''terrifying''. Sasuke [[OhCrap panics]].
** In their final battle, a few of the heroes' comments seem to trivialize Fubuki's sacrifices for the clan. Hishigi [[BerserkButton does not take it well]].
* The Devil Eyes in general, especially the fact that they are ''[[YourDaysAreNumbered eating Hishigi alive]]'', and are capable of taking over the minds of their hosts (demonstrated with Akari, and Hishigi's worst fear when he implanted them).
* Hishigi's experiments are [[UncannyValley creepy as shit]], but at least ''he's'' doing them for TheNeedsOfTheMany. Dr. White, whom Sasuke encounters on his own earlier, is a MadScientist who creates mutated ArtificialHumans and then keeps them imprisoned underground, vivisecting and otherwise torturing them for his own fucked up entertainment and desire to play god.
* Kyo's UnstoppableRage after Nobunaga almost fatally wounds Yuya.
* The rare breed children in Hishigi's lab swarming Sasuke and self-destructing, all talking about how he needs to die with them. This leads to...
** Shindara's death. The lower half of his body is completely destroyed in the explosion that he shields Sasuke from, to the point that even his regeneration is useless.
* A lot of the earlier fights in the series are gory to a T, especially since the main characters had no moral restraints back then
* The Demon Eyes look cool on Kyo, but do not look right on anyone else, invoking one hell of an UncannyValley effect - especially with the child experiment "failures", who look extremely off.
** The True Demon Eyes are entirely red (no sclera, no pupil) and really live up to the name.
* The Former Crimson King, a tyrant with [[AGodAmI a god complex]] who is [[ObfuscatingStupidity much more dangerous than he appears]], the fact he forces {{Synchronization}} onto priestesses for his plans with heavily implied perverse undertones, not to mention his other crimes. And then there's the intimidation aura he does to Yuya of several hands groping her...
** When Kyo is badly injured and collapses in his fight against Kyoshiro, the king appears to invite him into a LotusEaterMachine to forget all of his worries... only to try to murder him, made much worse since Kyo is a young child in this subconscious space.
* Chinmei, a "peace loving" psycho controls gravity, [[TheFogOfAges who has gone reasonably mad having lived for millennia, resulting in losing all of his sanity]]. Oh he also has [[RedEyesTakeWarning the True Demon Eyes]].
* When Akira fights Tokito, he uses his Inferno's Chill attack on himself to release pressure points that Julian activated with his needles earlier. This allows him to exceed the limits of his body for about five minutes, even opening his eyes and giving him hyperawareness. The nightmare fuel part is that this ''destroys'' him -- within one minute, he's curled up on the ground screaming in pain, and he has to ''get up and keep fighting'' because Tokito breaks out of his [[KillItWithIce Heaven's Chill]] technique and inflicts even more damage on him. We get the ''[[SarcasmMode lovely]]'' image of Akira's muscles ripping apart beneath his skin and his bones shattering from the strain. He tells Benitora later that he will most likely never be able to fight again -- Yuan's siblings are baffled that he can even stand with his left leg broken as badly as it is.