Arkham. While Vergil's role as an antagonist stems from his rivalry with Dante and a desire to become stronger, Arkham wants Sparda's power for the mass slaughtering of humanity and just for the sake of having it. Despite his Large Ham moments, he still somehow manages to make every scene he appears in completely devoid of humor, and his presence is just off-putting in general, what with his throbbing, pulsating veins on the left side of his face and his constant Death Glare. He speaks of the concept of "Evil" with religious fervor and delights in the fact that he used both Sons of Sparda and his own daughter for his nefarious ends, showing no mercy or regret when he stabs Lady through the thigh with her weapon's bayonet and when speaking of how he killed his own wife, Lady's mother. Vergil can be argued as being misguided to an extent, but Arkham is a complete psychopath.
His disguise as Jester, a creepy clown costume with a Gag Nose and black demonic eyes. He can be funny in this form, but it's still clear he's only being helpful to Dante for some ulterior motive, not to mention all the times he violates Dante's personal space. If you're afraid of clowns, his antics, laughter and sudden movements can be traumatic.
His transformation into Sparda's demonic form and, consequently, into a horrific blob of flesh and ooze with malformed parts all over it. His old face is still a part of the monstrosity, along with distended, elongated arms with clawed hands, spider-like legs and a mouth with sharp teeth, all of which constantly bloat and contract as he moves. And as an added bonus, this ugly blob form isn't a result of a power overload that was too much for Arkham. This disgusting creature is a mixture of Sparda's power and Arkham's rotten,corrupted heart. And he still thinks this is what Sparda's power is supposed to do.
Perhaps the scariest part about Arkham is simply the fact that he actually can't process the idea of human emotion and morality in any way, shape or form. Later villains in the series tend to dismiss them as simply things that make humanity "weak", but Arkham just never even sees the point in any of it, or even makes an attempt to understand it. He talks about his wife's murder at his hands like it was a simple requirement, has no qualms with hurting his own daughter to get what he wants and embraces the mass genocide of humanity like it's the rapture all because he wants to have the power of Sparda, who he says sacrificed a woman "to become a legend"... Completely missing the point that Sparda did it to save humanity and that the priestess was willing to do the sacrifice if it meant sealing away the demons. Even in his final moments, he screams at Lady as he asks "what did I do wrong?!" like she's simply bothering him, and even having the gall to ask her if it was "really so awful" and to help him, uncaring for how much of her life he ruined with his actions. He only realizes that he's completely screwed this time when Lady coldly wishes him goodbyeand pulls the trigger.
The enemies in this game can be really unsettling to some players:
As a good example, the Arachne demons (giant, deadly, half-spider-half-woman hybrid with loud screams) will be sure to give arachnophobes nightmares for a good while. Doesn't help that their nests in the two Provisions Storerooms have hanging human-shaped cocoons.
Soul Eaters, invisible octopus-like demons that will latch onto you and drain your health if you turn your back on them. It takes a quick reaction to kill them, since you can only do so when you aren't looking at them.
The Hell demons, each associated with the Seven Deadly Sins, most of them with metallic-like masks that are frozen in screaming expressions.
How about the Hell Wraths? Those pulsating bombs they carry that look like giant tumors, that horrible, tortured moaning, the fact that they could explode at any time...
On the same tune, the "Faceball" that Jester summons in his boss fight can spit said bombs at you... And they look like overgrown, freshly pulled out hearts.
Hell Envies, the guards patrolling the insides of the Leviathan, almost like they're the beast's immune system against intruders. Unlike the other Hells who simply roar or make deep-pitched groans, the Hell Envy monster squeals and hollers in a high-pitch.
The Demon World itself. In the previous two games, it was often depicted as a desolate, hellish landscape at best, and a Womb Level at worst. This version of it, however, is oddly serene. The "main hall" area is a bright white and it has human-like constructions and structures lying around, forming parts of the background. It looks disturbingly as if a church was pulled into Hell and twisted to fit the demons' views. The over world theme for the Demon World also fits with its odd dissonance. It kicks off Mission 18 and at first, it sounds rather angelic and heavenly (which serves as a good tonal call-back to Mundus' cathedral-like room in the first game), rather unfitting for the home of the demons... Until you play your way through the Lost Souls Nirvana, where it reaches its nightmarish portion of eerie chanting, whispers and odd instrumentation. And from that point on, the hellish part is the only part of the song that plays in the Demon World until you fight the bosses or enter one specific room.
The Temen-ni-gru tower is horrific if one starts to think it through. A giant structure created in worship of evil, acting as a connector between both the Human and Demon Worlds. Each room, when not under watch by demons or the Guardians, is eerily silent and empty, with the background music for each section of the tower giving this relentless atmosphere of isolation and suspense. The tower and its lowest portion, the "Forbidden Land", are both excellent in creating this feeling that Dante is truly alone with all the demons he has to fight.
The "Chamber of Echoes" room in Missions 4 and 5 has an eerie background track which includes laughing children.
The Chamber of Sins. A sewer-like room separated at the first floor, with piles of human bones on the ground.
The Tranquil Souls Room in the upper levels. Shelves upon shelves full of coffins and only dim candlelight to illuminate the area. There's not even the usual background track in this room, only the ambient sounds of wind and creaking wood.
The insides of the Leviathan, a.k.a. the Hell belonging to the sin of Envy. A proper Womb Level where we see, right at the beginning, that the Evil God-Beast has eaten things like a 16th Century ship, several modern-day skyscrapers, a part of a bridge, a car, and even an entire airplane. And most likely, those structures were full of people when the monster ate them. There's also the portion of Leviathan's Intestines where the Gigapede suddenly appears and chases you. And after you obtain a certain key item, Dante goes inside an intestine that's so pitch black, the camera only emits light around him. The Leviathan's stomach would also be almost dark when you return to it past this point.
Remember the Sin Scissor demons' creepy laughter from the first game? As it turns out, the Hell Vanguards in this game have the same sound effect, which is easily noticeable in a certain room where you backtrack and one of them spawns.
Horse-lovers may find Geryon a bit terrifying, especially with those terrifying neighs he makes...
Reading its library entry is both frightening and sad. Geryon used to be a legendary horse ridden by numerous heroes. But, over time it absorbed too much demonic essence/energy...and Geryon became a demon itself.
Then came Devil May Cry 5 with the reveal that the "Geryon" is a species of demon. There are more of these horses in the Demon World.
When you reach the 9000th level of Bloody Palace, the skies turn pitch black and three eyeless heads stare at the center of the stage with their mouth agape. It's unsettling, to say the least.
also fits with its odd dissonance. It kicks off Mission 18 and at first, it sounds rather angelic and heavenly (which serves as a good tonal call-back to Mundus' cathedral-like room in the first game), rather unfitting for the home of the demons... Until you play your way through the Lost Souls Nirvana, where it reaches its nightmarish portion of eerie chanting, whispers and odd instrumentation. And from that point on, the hellish part is the only part of the song that plays in the Demon World until you fight the bosses or enter one specific room.