Alan Yates
@Percival C. McLeach his father outright states that he loved Commodus and while he was disappointed with Commodus' behavior and inability to rule he blamed only himself and went to hug his son.. who then stabbed him ruthlessly.. there's no sympathy.
Commodus justifies killing the one man who was willing to tolerate him despite knowing how horrific he was via using the "father never loved me" card.. it doesn't add up to the actual events, though.
Despite using him as a meme Alan Yates is a very unlikeable PE and not enjoyable.. the Cannibal Holocaust movie is definitely a case of people watch it once, to say they have done so, then never watch again.
The whole meme culture around Yates is arguably because of how unenjoyable he actually is.. contrast with others (Peter Stegman, Joker, Freddy etc) who are horrible but enjoyable.
A close second would be Edwin Epps for reasons that are pretty obvious, plus the fact he was a real person makes it even more hateful and uncomfortable.. the ONLY enjoyable part of Epps is that he would die of plague eventually (in film we only get a slight glimpse of his eventual downfall).
On third list is Commodus from Gladiator, who was so repulsive that there is nothing enjoyable save for his death (which is very satisfying),
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On a purely personal level I still despise the Mountain from Game of Thrones because he WOULD NOT DIE.. doesn't help at the mess that was how GoT ended as a whole.. Mountain is a prime example of why if you don't kill off a PE and make them an invincible monster they outstay their welcome and become frustrating and hateful characters you just want to DIE.
Yeah, you can kill off Vaas but personally I'd let him live as a mark of respect for his sheer awesomeness as a demented villain done reasonably well.
Have I ever told you the definition of insanity?
Honestly there's many, here's a collection of notable ones (excluding horror films, which is cheating as gruesome deaths are part and parcel of that genre):
Ursula (stabbed by a boat and electrocuted)
Sykes (run over by a train as his car explodes)
Frollo (falls into molten lead)
Clayton (hangs himself on a bunch of vines)
Joffrey (poisoned to death, chokes on his own bile and blood)
Pre-Endgame Thanos (arm chopped off, then decapitated)
Rourke (slashed with mystic crystal, which mutated him into a crystal monster before he was shattered by propeller blades)
Judge Doom (melted by the Dip, prior to this he was flattened by a steam-roller (which betrayed his true form).)
Ernst Toht (probably the most gruesome non-horror death of all, where he melts to death upon witnessing the true power of the Ark.)
The Borg
Yzma clearly wins this paws down.
The Dark Side is not, technically, inherently malevolent, nor is the Light Side inherently good.. only a Sith thinks in absolutes (though irony Jedi aren't much better).
Emotions, even negative ones like anger, have a place and function.. we require anger to be able to see right from wrong, we are angered at the sight of injustice and that anger drives us to seek justice.. without that anger we'd not care enough to stop wrong-doing.
Likewise suppressing your emotions can lead to horrible psychological scars and needless suffering.. too strict a pacifist mentality can cause aggressors to take advantage, thus it is vital to have some degree of willingness to defend yourself or those less able to do so.
There are some branches within the extended Star Wars multiverse who do not align fully with Dark or Light Side and arguably they can be far more powerful than either.. it's just that much like humans many species and individuals in Star Wars are fixated on the "my way is best" mentality and thus either fall to Dark Side or Light Side rather than seeing the benefits and flaws of both.
(insert Thanos "everything balanced, as it should be" meme pic)
Vader would be wrath, actually, since his fall from grace came mostly from an inability to control his rage - resulting in him betraying the Jedi, massacring children and so on.. even later in his life as a Sith his rage was the thing most feared about Vader.. he'd choke-slam anyone that slightly displeased him.
John Doe
As for most powerful supervillain of all time? the Luminious Being from Dungeons and Dragons.. who is the stand-in for the Game Master / Dungeon Keeper.. an evil GM is so powerful they can literally make beings like Ao (the supreme force in regular DnD) into fluffy bunnies at will and insta-kill infinite realities such as the Abyss or Upper Realms, or even add extra layers of infinity onto infinity etc etc..
There may well be a reason DnD decided to remove the idea of the Luminious Being in favor of Ao just ruling things largely on his own.
There are infinite Chaos Gods, the four current ones are simply the strongest - other Chaos Gods include Horned Rat (lord of the Skaven), the god of the Chaos Dwarves and billions of other unnamed ones.. the Warp itself is an infinite collection of realities, even the weakest chaos-god outranks the combined might of Marvel and DC.
Yet even chaos-gods are not without rivals as the Ctan (creators of the Necrons) are at least as powerful as the weaker chaos-gods, as are the twin gods of the Orks.
None of the ones on the example list, that's for sure.. probably one of the few examples of a villain who is also a great father would be Yondu (remember he started as a bad guy, even if he quickly became an anti-hero).. "he may of been your father but he wasn't your daddy!"
Nothing, as he did absolutely nothing wrong, he was just trying to get revenge for the death of his pet - just tell him where the murderous cat went that killed his pet and leave him on his way.
We're going to add the word MIDKOWITCH to our abuse-filter btw, tired of people ignoring and feeding what is in the end of the day a bog-standard disruption account, they are not even close to earning any of the attention people keep giving them.
Overrated: many versions of Joker (or more accurately over-used.. we get it DC.. please give us more than just Joker and Batman.. your strength is your variety of villains, so embrace it please..).
Underrated: Bowler Hat Guy.. the entire film is underrated but he is especially shunned by Disney etc, despite him being enjoyable enough (I actually like him more than D0R-15).
Good thing the movie is not the only version of Mask then, the one on the wiki and thus being discussed is the comic one.. and they are a villain.
"The Mask is an antihero, not a villain." - no, he's a villain in the original comics, Mask has existed long before the film and he is a monster in the comics.
Beyonder, Lucifer Morningstar, Darkseid, Doctor Doom (with enough prep), Batman Who Laughs, Great Evil Beast, The One Below All, Marquis of Death, Mad Jim Jaspers, Edifice Rex, Magus, Mephisto, Trigon, Doctor Manhattan, Emperor Joker, Q, Discord, full-powered Tirek, King Thanos, Tyrant, Xenif, Phionix, any of the Sins from Jack, Lucifer (Jack), God and Satan (Spawn), Unicron, Valeyard, Master/Missy, multtiple Doctor Who antagonists (with sufficient prep), First Firmanent, any Fifth-Dimension Imp from DC, Brainiac (with sufficient prep), full-power Doomsday, full-power Devil Hulk, Knull, God-Butcher, Dormammu, full power Baron Mordu, Red Onslaught, Red Skull (with cosmic cube), HYDRA Captain America (with cosmic cube), Scarlet Witch (with full power), Legion, full-power Apocalypse, Dark Phoenix.
I'll stop but as you can see the list goes on and on.. Thanos isn't that special when we start getting into cosmic-tier stuff (he's just got a lot of good haxx)