A good protagonist can provide a game with a heart and a soul, but it is hard for a protagonist to stand out if they aren't confronted by a powerful opposing force - an intimidating antagonist. These figures are a means to test the hero and to help define their heroism.Some of the most noteworthy antagonists will, at first, seem like an impossible force to overcome, which of course makes the hero's victory seem all the more impressive. These villains often end up staying stuck in our minds long after we complete the games, which is a testament to their immense presence and their ability to test our resolve.
10 Balio and Sunder, Breath Of Fire 3
These two primarily act as muscle for the mob. While they may seem like early game antagonist fodder, they deserve a little more recognition than that. When you first face off against them, they are overwhelmingly powerful. In fact, they essentially kill Ryu. Twice.
Balio and Sunder are the primary antagonists Ryu faces in his youth. When you do finally beat them, that victory helps establish how much Ryu has grown. More powerful antagonists would appear after them, but none would be as intimidating. These two weren't horsing around.
9 The Reaper, Persona Series
The Reaper isn't a part of the story in Persona 5, so he isn't intimidating from a narrative perspective, but he is an overwhelmingly powerful boss who will attack you if you move too slowly in a dungeon. Which, functionally, means that the Reaper exists solely as a means for intimidating the player. If you aren't prepared, The Reaper will absolutely annihilate you.
This enemy doesn't just have extremely high defense, but he also has the ability to kill any party member with an instant death attack. So yeah, you are going to sweat when he pops up in a dungeon. Forget what that one song says, you should fear The Reaper.
8 Magus, Chrono Trigger
While some may think of Magus as being one of the protagonists of Chrono Trigger, they are forgetting that he is the primary antagonist for the first quarter of the game. Arguably, he is the most intimidating of all the antagonists. Magus is an extremely powerful wizard and rules over the middle ages era in Chrono Trigger.
While he does have his own motivations, he is completely unconcerned about those who he harms along the way to achieving them (more concerned about the "greater good"). Ultimately, despite being one of the earlier bosses, Magus is almost certainly the most intimidating one of the bunch. Even his theme song is strikingly ominous. Basically, intimidation is the guy's whole personality.
7 Sephiroth, Final Fantasy 7
While Sephiroth seems to exist purely to harass Cloud in the Final Fantasy 7 sequels, it is important to remember how the character was portrayed in the original title: Sephiroth was a dangerous enigma. You knew very little about his motivations. What you did know is that he was incredibly powerful.
The Shinra HQ scene feels like something out of a horror movie. Our heroes are mysteriously released from their cells and follow a giant trail of blood and corpses all the way to the president's office, only to find that Sephiroth has left a sword as a souvenir sticking out of the back of President Shinra (who had been the primary antagonist of the game up until this point). We may not have known his motivations, but what we did know is that he wasn't to be messed with.
6 Joker, Persona 2: Eternal Punishment
There are two Persona 2 games (Innocent Sin and Eternal Punishment) and alongside these two Persona 2 titles, there are two Jokers (both different people) who act as antagonists. Confused? That's understandable. Here we are specifically talking about Eternal Punishment's Joker. By all means, he isn't nearly as much of a threat as the Joker from Innocent Sin, but you could absolutely argue that he is far more intimidating.
What Joker lacks in late-game plot significance, he makes up for in presence. From your first encounter with him, you instantly understand that his whole aesthetic is intimidation. Joker is like something out of a Japanese horror movie; if you call your own phone number, he will kill anyone you name - and he isn't all talk, either. Joker kills multiple people in a short span of time. He doesn't stay for long, but during his moment in the spotlight, he leaves an impression.
5 Ryuji Goda, Yakuza 2
Until the most recent entry, the Yakuza series was largely the story of Kazuma Kiryu. However, by the end of the first game, it had become readily apparent that Kazuma was not a man to be trifled with. So, Yakuza 2 did what many great series do; they created an antagonist who mirrors their protagonist.
Ryuji is to Kazuma what Venom is to Spider-Man. Ryuji pursues Kazuma almost entirely out of pride and respect. Ultimately, he is the one example of an antagonist who appeared to be just as strong as Kazuma - and fighting against anyone that has any claim to the kind of strength that Dragon of Dojima has is frightening.
4 The Countess, Darkest Dungeon
Damn near every creature in Darkest Dungeon can be a threat, and this is a game where failure can have extraordinarily dire consequences. The Countess is the culmination of all of that. Moreover, The Countess ramps things up considerably by being a particularly brutal fight.
In one form she has a ton of resistance, in another one of her forms she cures all of the effects you have placed on her, and in her last form, she murders you with her horrifying array of powerful attacks. This fight with this Lovecraftian debutant is difficult and, if you don't come prepared, she will destroy your best characters with a number of frighteningly powerful attacks.
3 Kefka, Final Fantasy 6
Kefka is not particularly strong. Final Fantasy 6 goes out of its way to make that readily apparent from the get-go. You have several encounters with him in the earlier half of the game; in none of those battles does Kefka come across as much more than a nuisance. What, then, makes this sadistic clown so intimidating? Well, first and foremost, Kefka has a willingness to do anything.
There is no twisted moral code or sentimental attachment to another; he isn't that kind of antagonist. Kefka is motivated by his own self-interest, which is power for the sake of power. He is cruel, manipulative, and willing to do literally anything, including destroying the entire world on a whim. Kefka doesn't start off feeling like much of a threat, but by the end of the game, you understand that it was a grave mistake to underestimate him. But by then it is too late.
2 Adam, Nier: Automata
Adam is one of the primary antagonists in Nier: Automata's routes A and B. Things start off on an awkward foot, as the player witnesses Adam's birth - which is more than a little unsettling. From there, he quickly demonstrates his immense power (while barely even fighting back).
The whole encounter is deeply off-putting. You walk away from it with a lot of questions and a number of doubts. Soon after, you are being hounded by the android (alongside his brother, Eve). While his motivations remain nebulous, his power is unquestionable.
1 Luca Blight, Suikoden 2
The one-sided angry evil man is, at this point, such a cliche that most franchises do their absolute best to avoid it. There is a reason for this: these characters can be a little boring. Suikoden 2's Luca Blight, on the other hand, exists as the sterling example of how that doesn't necessarily have to be the case.
Luca Blight is almost certainly the most powerful warrior to have ever appeared in a Suikoden game. He is also a ruthless sadist driven by violence. He isn't defeated by a single party; you have to assemble multiple parties of characters in order to stop him (over the course of multiple battles). Long after Luca Blight is dealt with, his image will still be burned into your mind. He is the platonic ideal of intimidating antagonists.