Satan in Castlevania: Lords of Shadow

Big Boss in the Metal Gear series

Others I would've mentioned have already been listed.

Albert wesker from resident evil

He's hilarious, charming, and reprehensible all at the same time. What's not to like?

I've noticed that both Jack and GLaDos seem to show up the most in discussions like these. I think it's not only because they're incredibly well-written, but because of their relationship to the player. They spend much of the game interacting with the player in some form or another, and the relationship between you changes over the course of the game. It makes for an engaging dynamic with the antagonist that gets the player involved in the conflict.

Enjoyable? Elexis Sinclraire of course!

Killbane, from Saints Row 3. Oh, and that belgian guy from the same game.
Oh, and I nearly forgot Handsome Jack. :-)

You mean Phillipe Loren i think. Regarding Saints Row, Zinyak from SRIV is also pretty cool.

The Joker from The Arkham serie but the Joker is one of my favorite character in all media since i was young
and The Reapers from the mass effect trilogy, they are creepy and very powerfull, i was wondering since the end of the first game how will we defeat them.

My response is one that everyone and their grandmother, dog and goldfish already expected. Its the Ur-Quan race. They're perfectly done villians in their own right, but the stuff between the lines makes them stand out. No other game ever made me emphasize with a villian like Star Control 2 as they're just so well established within its own universe in such a simple way. Anything about them not even done in a suprising way. Like they're not even plotwist, the entire game feels like one full gradiant plot twist where you understand that the tragic villian is actually one that tries to be the hero in their own perverted fashion (at least the Kzer-Za have that mental projection in mind while the Kohr-Ah simply do what they feel is right, which makes absolute sense considering the reason why they exist).

What makes the Ur-Quan stand out compared to other mentioned villians is that two Ur-Quan races are a perversion of their own perfect self. Remember that their entire lagacy up to their own genes has been raped by the Dnyarri (raped seems to be good word, though it is several times more worse than "just" rape what has happened to them). Its like both the Kzer-Za and the Kohr-Ah can never become happy or whole again due to the past history. They've simply been touched in ways no other individual or race never has been. Its just so tragic and perfectly pulled off that I'm still trying to wrap my head around. No other game in the past few decades compare to the elegance in creating way more depth with way, way less than even modern games that try to pull off similar narratives.

Its also perhaps too mature and too dark for its own good, considering a lot of dialogue that happens in the game is actually funny and not really about the main villains at all. While the themes of things such as the eternal doctrine war is also a perfect metaphor of fighting with yourself, suicide and depression all put together in a blender of full-pants-on-fire-self-loathe that makes up quite a bit of story. Its written in such a way that you don't even notice it at first. Only some subtle things such as realizing that the different indivudals from the same race all look the same is a good way to imply that race = person, which initially transpired due to the lack of resources to create different sprites, then they put in suble dialogue so people can connect the dots of what the writers want to convey. Its like they throught of everything in advanced and had to use the funds to the maximum (all the voice action were done by the staff that made the game, as well).

So all in all, the fates of the Ur-Quan is a fate both worse than death and hell inself in no particular order, and thats the most positive outcome of the situation they're in. Literally the only villian that comes close to such perversion is Allied Mastercomputer, who felt the only reason to live on is to show a small portion of humanity what it feels like to be in its own shoes. But that villain stems from a short story and is not from a game alone.

So even if you emphathize with them they're also way past the point of no return. The Ur-Quan races are the type of villian who severely deserve a hug while you must stab them with a knife for their own sake. They're not just evil to the point where it seems comical, but paradoxically in a way that they're seemingly senselessly but also reasonable evil, depending on your own empathy. Kinda akin to a genius-madman who still makes sense even if the evil they're doing is foreign to everyone else but them. Its not easy to come with with such a intricate villian that feel both very easily understood but overly complicated to the point where they become literally alien for everyone but themselves, because they've lived through the things only they can ever fully understand.

And how could you even fathom a personal hell if you've never experienced one yourself? Would that experience alone turn you into a crazy monster and if not, would that experience actually be something else entirely? When do things actually reach the event horizon if you keep pushing (yourself or others) into placed where one should never get pushed into? These specific thoughts still haunt me randomly every once in a while to this very day for over 25 years now. Never found the answer through any medium ever though.

Because this game asks question nobody ever dared to ask before in a video game in a way that almost feels to grand for the medium I believe that the Ur-Quan race is the most enjoyable villian in a video game, ever.

EDIT: If you're confused what "Kzer-Za" and "Kohr-Ah" mean when I'm talking about the Ur-Quan. Well, its...complicated. What are you even doing with your life if you've never played Star Control 2 so stop wanking to porn while browsing the forum and play the damn game already.

The main character you play as in the game Braid.

It was a really shocking plot twist for me when I found out that in this super mario like game where you try to rescue the princess in the castle only to find out that you are the evil monster she was running away from.

Elder God in Soul Reaver games. One can't simply say no to Tony Jay.

Yeah, especially Magnus Armstrong, Baron Dumas and the Director for me. But all are great. That one as well.

I see your point.