A feared Villain doesn't necessary to look ugly and scary (it help though), what makes a villain to be a feared opponent is a combination of many things, evilness, super powers, deeds, look and other things, here are my picks starting with 10.
Spoiler Warning: If you don't want to spoil the games these villains appear in just don't read the description as most will have spoilers.
10. Diablo (Diablo series):
Demons are the essence of evil. Just saying the word "demonic" conjures up all sorts of imagery and thoughts about strange rituals, the spilling of blood, and a host of other things Sunday school teachers warn kids about. But demons are also freaking cool to look at, and even better to fight if you want to go on a righteous quest. Drawing on these universal thoughts about the nature of demons, Blizzard created the Lord of Terror, Diablo.
Diablo is, for all intents and purposes, Blizzard's take on the stereotypical imagery for the Judeo-Christian demon Satan. A gigantic red demon, Diablo uses fear to manipulate humans, often making them see violent things. He is the final boss of the titular Diablo game, and is one of the three most powerful demons in the game's world. He was slain in the first game, only to then possess the body of the very hero who destroyed his demonic form. While he was also once again vanquished at the end of Diablo II, Blizzard has since confirmed that he will be in Diablo III. Will the Lord of Terror finally be destroyed the third time around? Probably not -- he is a demon, after all.
9. Alma Wade (F.E.A.R.):
Whether this girl was inspired from Straub's novel or by Samara from The Ring, Alma is terrifying. She always shows up around random corners, or she'll be standing at the top of a ladder, waiting for you to make your way up. Alma was designed to "get under the player's skin" according to the developers, and boy did they succeed. From the horrific dream sequences that Alma creates to the physical manifestations of her that pop up throughout the game, there's no end to Alma's terror in the first FEAR.
What really made Alma so scary and such a cool villain has nothing to do with the power that she wields, it's how the developers chose to use her. Lead designer Craig Hubbard said he wanted to give players, "enough clues so that [they] can form [their] own theories about what's going on, but ideally [they will] be left with some uncertainty." One attributing factor to this being realized was the sound. The developers did a wonderful job of crafting all sorts of horrific effects using low-tech solutions that paid huge dividends with the end product. No matter how similar Alma might seem to Samara and other horror characters, any gamer worth their weight in blood will tell you that she' a villain in a league all on her own.
8. Cyberdemon (Doom series):
This is one mean son of a *****. The cyberdemon is the end boss for the first and second Doom games from developer id, and he presents a serious challenge to players. He has a reported 4,000 hit points, he's the fastest character to appear in the first Doom, and he receives no splash damage from explosions. Even the mighty BFG9000 can't take him down in one shot. If you're lucky, you'll bring him down with two, but in most cases a cyberdemon will take three or four charges from the Big Gun. In other words, killing this guy isn't the easiest thing in the world, especially when you factor in the barrage of rockets that he constantly spews out. To bring him down, you'll need a lot of ammunition in your possession. To wit, it'll take around 40 rocket shots, 400 chaingun bullets, 25 point-blank double-barrel shotgun blasts, and you can forget about melee attacks. The cyberdemon may not be the most cunning villain in terms of mental capacity, but there's no denying that his brute strength makes him a worthy foe for any gun-toting hero.
7. Nemesis (Resident Evil 3):
Coming after the blockbuster Resident Evil 2, Capcom needed something pretty spectacular for the third game. Enter Nemesis. While there is no shortage of zombies and monsters in Resident Evil 3, the primary bad guy is the seemingly unstoppable Nemesis who shows up from time to time to kick your butt from here until next Thursday. Born in Umbrella Labs as an upgraded Tyrant, Nemesis actually has the brains to actually walk around objects whilst in pursuit of its prey. Trust me, this was no small innovation to Umbrella line of custom-made zombies.
Capcom dressed this monster up in serious motorcycle gear, complete with a black leather overcoat and platform boots. It carried a rocket launcher into battle, but when simple shells weren't enough to slow down Jill Valentine, Nemesis mutated to grow - wait for it - tentacles.
But it wasn't Nemesis' brains and tentacles that made it so terrifying. It was its persistence. Nemesis doesn't stop. Ever. Shooting it in the face with a shotgun? Minor flesh wound. Acid bath? It shakes it off by noshing on a Tyrant and absorbing its poison-spitting power. It finally took a prototype rail cannon to drop this brute, and even then, the members of STARS still look under the bed at night to make sure Nemesis isn't there... waiting.
6. Pyramid Head (Silent Hill):
Pyramid Head is the name James Sunderland uses in reference to a monster who is arguably the main antagonist of Silent Hill 2, and the most well-known and iconic monster of the series.
Across the series he is usually portrayed as, at his most basic, a violent monster. A deeper meaning given to him, however; sees him as a kind of punisher or executioner. He's typically attracted to those who feel an extreme amount of guilt or have an overwhelming desire for punishment. His acts of violence are not aimed solely at humans, as he has also brought harm to the other creatures that inhabit Silent Hill, hinting at a neutralness or even no relationship at all to the town or the Order's God, making him an individual being.
5. Darth Vader (Star Wars series):
You need only cover your mouth and take a few deep breaths for someone to immediately know that a Darth Vader impression is forthcoming. Vader has been in countless Star Wars games, but probably his most notable appearance was in Star Wars for the Famicom. In this very early Star Wars game, Darth Vader makes his first sinister appearance in... wait for it, a sand crawler on Tattooine. He starts swinging his light saber at you, and after one hit turns into... a scorpion? In later fights he transforms into a shark, a pterodactyl and a yeti. Remember that part in the movies when Darth Vader turns into a shark and starts biting Luke?
In all seriousness, though, the guy blew up planets. Entire freakin' planets. Sure, most of his villainous actions were from the films, but he had some notable appearances in games too. Although he's technically your ally in Force Unleashed, the opening sequences has Vader slaying wookies and jedi left and right, and is the sole reason you - as Starkiller - are out slaying rebels. It could also be said that his inclusion in Soul Calibur IV was villainous on the part of Namco. Lightsaber not cutting through the regular sword? Blasphemy.
4. Dracula (Castlevania series):
Count Dracula was a character created by Irish novelist Bram Stoker in the late-19th century, and ever since, his legacy as a multifaceted fictional being has transcended both time and medium. In the realm of gaming, there are several franchises that utilize a vampire theme, but none even remotely as popular as Konami's Castlevania franchise, where, for the most part, Count Dracula remains a strident mainstay of the series. Indeed, it's his ghastly, enemy-filled castle that gives the famous franchise its name in the first place. And as far as persistent villains in gaming's past are concerned, Count Dracula is no doubt near the top of the list.
The premise of Castlevania is simple enough to comprehend, and it's Count Dracula that's always at the center of the intrigue. Every one-hundred years, Count Dracula has a nasty habit of resurrecting himself from the dead, spawning a massive, treacherous castle, and subsequently plaguing Eastern Europe with his undead minions, driven by an unquenchable thirst for blood. The Belmont family has long done battle with Dracula, and it's their family's job to quell any threat the vampire leader poses, which is at the heart of the early Castlevania titles. Of course, games in the series are released to this day, and though many deviate from the old-school plot in one form or another, you can rest assured that Count Dracula is almost always behind whatever disturbance is currently being dealt with, making him one of the more prolific villains in gaming's history.
3. Sarah Kerrigan (StarCraft):
Sarah Kerrigan was originally an elite hero in the StarCraft universe. However, doing her duty to the final hour, she eventually fell to the evil Zerg on the planet Tarsonis. Presumed dead, she reemerged during the course of StarCraft as a mutated version of herself -- a genetic mish-mash of human and alien DNA, and the Zerg second in command. While she eventually took control of the Zerg through murder, deception and betrayal of her former allies, her humanity appears to have been forever lost, with only the vaguest of emotions being shown for her old friends.
Now in command of a vicious swarm of DNA stealing aliens, Kerrigan ultimately has taken up the goals of the Zerg: nothing short of consuming the entire universe. Though in the many years since StarCraft: Brood War she has kept her forces at her heel, the Zerg will likely explode with a frenzy back into the many worlds of StarCraft 2, with Kerrigan at the helm of the most powerful enemy force the universe has ever seen.
2. Albert Wesker (Resident Evil series):
Nothing's worse than someone you trust stabbing you in the back, and Albert Wesker is the ultimate betrayer in the survival horror franchise Resident Evil. Once the team leader of an elite unit called S.T.A.R.S., he willingly led his team into the path of a deadly virus to suit his own purposes. Not content with this betrayal, or to have the good sense to just die like he leads you to believe at the end of the first Resident Evil, Wesker has returned time and again throughout the series to torment the many people whose lives were affected by the virus he helped set loose.
Through the many years and games he's become more and more evil thanks to the T-Virus he infected himself with in order to survive the mortal wounds he suffered in the first Resident Evil. Imbued with superhuman strength and endurance, Wesker has moved from being a double-agent working to kill his own team, to an evil-tyrant seeking to infect the world with a virus that will turn them into zombies. While he was killed at the end of Resident Evil 5, and has since been confirmed to be really deceased, he's undoubtedly one of the more memorable villains in recent memory.
1. Sephiroth (Final Fantasy VII):
Although the nemesis from Final Fantasy VI, Kefka, could be considered a more devious villain, Sephiroth is arguably the most iconic antagonist of the Final Fantasy franchise. Originally a hero of Shinra's SOLDIER division, Sephiroth was driven mad by the chilling knowledge he found at Nibelheim mansion. After discovering that he was in fact a product of Shinra's biological experiments, Sephiroth destroyed the village of Nibelheim and ignited the confrontation between himself and Final Fantasy VII's hero, Cloud.
Sephiroth is incredibly strong physically and is also skilled at the use of magic. Although he faces the heroes of Final Fantasy VII throughout the course of the game, it is revealed at the game's conclusion that his true form was in stasis at the Northern Crater all along. Sephiroth takes on multiple forms to battle Cloud and his friends, but is eventually bested. This is not the end of Sephiroth, however, as he also appears in several Final Fantasy spin-offs like Crisis Core, Dissidia Final Fantasy, and the CG film Final Fantasy VII: Advent Children.
The image of Sephiroth standing amidst the burning ruins of Nibelheim is second in infamy only to his shocking fatal blow against Final Fantasy VII's heroine, Aeris.