Black Manta: He is the archenemy of Aquaman. Black Manta may seem pretty lame because of that, but he did something that at the time not even someone as crazy as The Joker did. Black Manta captured Aquaman's son Arthur Jr. and made Aquaman and Aqualad fight to the death, if they didn't... all the while Arthur Jr.'s oxygen was getting cut off!!! In the end, Black Manta killed Aquaman's baby son, sending Aquaman into a deep depression and making his wife Mera go insane. Joker may have killed the boy wonder, but Black Manta killed Aquaman's baby son and cut off Aquaman's arm. Now that is what I call a villain.
Red Skull: Red Skull is the ultimate Nazi in comic books. Yes, I'm saying that he is an even better villain than Hitler in some aspects. He has been ruining the lives of thousands ever since the 40. He started as a basic Nazi but was soon promoted to higher statues due to his sick twisted personality that even had Hitler afraid of him.Not only this, but ed Skull seems to never die. If you think you've killed him, you're wrong. He will most likely just come back in a new body and go back to killing. Even when he was "dead" his massive army were still powerful enough to be a constant threat to Captain America and the rest of the MU. One last fact for everyone, Red Skull was the first Marvel super-villain.... or at least the first to become a major threat.
@jhazzroucher: @The Poet: Now after a lot of though (AKA just calling my cousin) I've decided to choose Helspont. Keep in mind that this is only what I read about him, so bear with me.
Helspont: Helspont ins a huge villain in not only the WILDcats comics, but the entire Wildstorm universe. Helspont was just a dangerous villain that there had to be not one, not two, not even five, but SEVEN teams created after he attacked. Helspont is also notable for the fact that he has had plans to take over the world a lot! One time he even teamed up with Dr. Doom and the skrulls! (more to come)
The Violator - Arch enemy to Spawn, The Violator has been murdering people and fighting Spawns for centuries. Not only that, but he possessed another one of Al Simmons enemies and used him to nearly beat Al to death!
The Governor - Its the zombie apocalypse, and all you want is some nice safe shelter. You come upon a town called Woodbury, but instead of getting some shelter and food, you are forced to fight for your life against zombies for The Governor's own sick pleasure. He is the main villain other than the zombies, and has proven this by killing several main characters, even raping one. In the last couple of pages he is in, The Governor manages to kill main character Rick Grime's wife AND newborn baby.
Overlord - Savage Dragon's arch-enemy. Overlord basically owned all of Chicago thanks to his vicious gang The Vicious Circle. Even though Savage Dragon eventually killed Overlord, it doesn't mean he lost easy. In their first encounter for example, Overlord bet down Dragon severally.Oh and in classic villain style, anyone who failed Overlord would be punished. And in Overlord's case, he would punish you, by incinerating you!
The Shredder - Like the Joker, Shredder started off as a one-time villain, but was seen with a lot of potential, hence why he has returned so many times. Also like the Joker,Shredder went from being dark and ruthless, to corny, and then back to being dark and ruthless. The Shredder was the most wanted person in the galaxy at one point. He is also one of the most recognizable villains in comic history, even though he was only created some 25 years ago. Even though Shredder died in his first appearance, his legacy lived on. He has since became things like three clones, a robot, a demon, a mutant shark, and more. Now how many villains can honestly claim that they've been a demon from hell and a mutant shark? Not much, not much.