'''Satan'''
* AffablyEvil[=/=]FauxAffablyEvil: Zigzags the two. To most people, he's FauxAffablyEvil, often utilizing ExactWords to make people think he's about to give them what they want before making their torments even more painful. To other supernatural beings and the handful of humans he respects, he's AffablyEvil; he'll still torture them if they become annoying, but when he's not doing so, he's fairly friendly and can sometimes even act as a caring presence.
* AntiHero: Type V.
* BadBoss: He's not much nicer to his demons than to his captives. He once made Scumspawn eat himself.
* BadLiar: Ironically, he's terrible at coming up with believable lies.
* BeingEvilSucks: He's borderline suicidal as a result of running Hell.
* DarkIsNotEvil: At least nowhere near as evil as you'd expect him to be, especially compared to Thomas.
* DeadpanSnarker
* TheDevilIsALoser: He's a rather whiny, borderline-suicidal fellow who uses torture and corruption mainly as a mechanism to cope with his own self-hatred.
* EvenEvilHasStandards
* EvenEvilHasLovedOnes: He gets a one-shot love interest named Hope in one Christmas special. He also cares more about Scumspawn and the Professor than he lets on.
* GreenEyedMonster: The Professor often notes (to the point of it being a catchphrase) that Satan torments humans because he wants to bring everyone down to his level- he hates himself and his situation and wants everyone to be as miserable as he is. For extra points, Satan is actually described as having green eyes.
* HorrifyingTheHorror: He horrifies all the other demons, and is himself frightened of the wrath of God.
* {{Hypocrite}}: One of the main reasons for his hatred of humans is their refusal to own up to their mistakes, yet he continually objects to any attempt to blame him for his own rebellion against God and subsequent banishment from Heaven.
* KaleidoscopeEyes: At one point when Satan is losing his temper, the Professor notes that his eyes have gone purple; then, a little later, [[BlackEyesOfEvil completely black]].
* KickTheSonOfABitch: Most of the punishment he inflicts upon Thomas would be disgusting, but given how Thomas is a monster it's hilarious. Case in point: trapping him under an incontinent hippo for most of an episode before he eventually removes it... [[CrowningMomentOfFunny only to dump an incontinent and heavier rhino in its place]]. The rhino then tramples him before it goes off.
* LouisCypher: We always know who he is, we just don't know who he's pretending to be.
* NobleDemon
* PaperThinDisguise: He may be able to change his shape, but humorously, doesn't do much (or often anything) to change his voice.
* PayEvilUntoEvil
* PetTheDog: Every now and then.
* {{Satan}}
* ShroudedInMyth: He wasn't the snake in the Garden of Eden, nor was he responsible for Job's misfortunes.
* UnsympatheticComedyProtagonist: He ''is'' the devil, after all.
* VillainsNeverLie: Whenever he makes a claim about science or history that contradicts our current knowledge, it will turn out to be accurate.
* VillainProtagonist
* WouldntHurtAChild: Satan has strict standards of not possessing anyone who isn't old enough to make moral choices, and is thus in one episode is shown to be [[EvenEvilHasStandards enraged]] at fundamentalists who believe a child is possessed by him, and want to beat Satan out of the child.

'''Thomas'''
* AnythingThatMoves: Has sexual feelings for cartoon characters and mannequins. [[HaveIMentionedIAmHeterosexualToday As long as they're female, of course.]]
* TheAtoner: Averted. The Professor, and then Scumspawn, spends a lot of time trying to reform Thomas. He doesn't really get it.
* BadBoss: When he was alive, he drove one of his employees suicidal. When he finds this out, [[EvenEvilHasStandards he seems to be genuinely remorseful]], [[JerkWithAHeartOfJerk only to then say that it's her fault anyway for not complaining enough earlier]].
* BeingEvilSucks: Sort of; it worked out great for him when he was alive, but then he died and went to Hell because of his evil acts.
* ButtMonkey: Satan's personal punching bag, particularly because [[EvenEvilHasStandards Thomas disgusts even him]].
* TheCasanova: In life, he was pretty successful at seducing women.
* CorruptCorporateExecutive: Was one when alive.
* EvenEvilHasLovedOnes: He values his friendship with Scumspawn deeply.
* EvilRedhead: Stated to be red-headed in series six.
* FauxAffablyEvil: Thomas is [[Series/TheNewStatesman Alan B'stard]] on steroids.
* {{Flanderization}}: To an extent. In the first series, he's more of a malevolent cad, but later episodes present him as a rage-filled psychopath. Weirdly, this happens at the same time as efforts are made to reform him.
* NeverMyFault:
** After marrying Edith's daughter, he tormented her to the point of insanity. He eventually accepts 3% of the responsibility for the marriage's failure, which Scumspawn notes is 3% more than last time.
** In another episode, Thomas argues that his being in Hell is unfair as his evil acts were predetermined as part of God's plan. After God tells him that God's plan doesn't exist and everything he did was out of his own free will. He then says that [[InsaneTrollLogic it's still God's fault for being stupid enough to give people like him free will.]]
* NotSoHarmlessVillain: He's more of a punching bag than a villain by the time of the series. However, in life, he murdered, raped, and tortured god knows how many innocent people, and was able to get away with it completely until [[AlwaysABiggerFish Satan found out about it.]]
* PetTheDog: [[spoiler: literally, in season 7]].
* [[spoiler:SemiDivine]]: His [[EvilRedhead red hair]] [[spoiler:marks him as having angel ancestry, though he has no powers.]]
* UnsympatheticComedyProtagonist
* UpperClassTwit: A particularly malevolent one.
* VillainOfAnotherStory: When he was alive, he murdered, raped, and/or tortured many people, but since he's already gone to Hell by the time of the series he's more of a ButtMonkey than a villain.
* VillainProtagonist: The focus of most plotlins he's involved in.


'''Gary'''
* AffablyEvil: Quite polite despite his love of cruelty.
* ButtMonkey
* [[spoiler:TheStarscream]]

'''Scumspawn'''
* AmbiguouslyGay: For Satan. He's a bad chooser.
* BumblingSidekick
* MinionWithAnFInEvil
* MoralityPet: For Thomas in later seasons.
* GeniusDitz: He is totally naive and incompetent, but is secretly an incredibly talented musician and artist. At one point, he is able to BUILD ROBOTS.
* ChasteHero: His love for his master is totally non-sexual. [[BarbieDollAnatomy Then again]], it kind of has to be.
* ExtremeDoormat: He once ate himself because Satan told him to.
* TokenGoodTeammate: The only good demon.


'''The Professor'''
* DidYouJustFlipOffCthulhu: He often attempts to assess Satan's psychology. Most of what he comes up with is not very flattering.
* FlatEarthAtheist
* HeroAntagonist: In most plotlines involving arguments between him and Satan.
* MoralityPet: Essentially is this for Satan.
* WideEyedIdealist: His idealism is shattered only once during all seven seasons of torment. [[MomentOfAwesome He gets over it.]]
* StraightMan
* TokenGoodTeammate: The only non-evil character in the main cast until Scumspawn appears.
* WorthyOpponent

'''God'''
* AffablyEvil: Is generally respectful of those he speaks to, wishes his angels were more willing to lighten up and joke around and frequently sends people to Hell for little-to-no reason.
* AttentionWhore
* BerserkButton: Don't question whether he's the one true god or not, or call him by his real name-[[spoiler:Nigel]].
* {{Jerkass}}
* ShroudedInMyth: He's not actually omniscient, and most of the miracles in the Bible never actually happened.

'''Edith'''
* CoolOldLady
* {{Determinator}}: As Satan notes 'arguing with her is like... well it's like cornering a badger'.
* SuspiciouslySimilarSubstitute: [[spoiler: introduced after the Professor leaves and plays a similar role.]] Played with in that there are notable differences between the two characters; where [[spoiler:the Professor's idealism]] comes from trying to find the bright side of every situation, Edith's comes more from romanticizing certain people, ideas, and events while seeing no good in others. Also, while [[spoiler:The Professor]] came to be fairly well-liked even by the villains, Edith is tolerated at best by most of the other characters.
* StraightMan

'''Jane Austen'''
* AxCrazy
* ShroudedInMyth: She's absolutely nothing like you'd expect from her work, or even from historical accounts.

'''Adolf Hitler'''
* NeverMyFault: He maintains that the Holocaust was merely overreacting to being filmed in the shower, and he blames his failed invasion of Russia on Jesse Owens.
* UltimateEvil: He's the most frequently mentioned out of all the historical figures, but he never speaks, is never spoken to, and other than one scene where he is explicitly in disguise, is never even spoken about in such a way that one can infer his presence.

'''Nero'''
* AGodAmI: Claims to be a god.
* HorrifyingTheHorror: When he's temporarily put in charge of Hell, [[EvenEvilHasStandards his cruelty horrifies even the demons.]]
* OneShotCharacter

'''Chuckles the dolphin'''
* IntelligibleUnintelligible: Speaks like an actual dolphin, but Satan understands him.
* OneShotCharacter
* SapientCetaceans