Chosen from the ranks of the Legion of the Unliving. These boys were all alive at some point, but after they died they were resurrected by the Grandmaster and sent to fight the Avengers. Korvac, Terrax the Tamer, Baron Blood, and Death Adder.
Their claims to fame:
Korvac stole the Power Cosmic and killed a bunch of heroes, notably Captain America and Wonderman (don't worry - they got better).
Terrax the Tamer was a Herald of Galactus, but never seemed to be able to get his shit together and gets played around by Doctor Doom, the Fantastic Four and Annihilus. Although he HAS destroyed at least one planet in its entirety.
Baron Blood is a Nazi-acrobat-vampire (as you do) who was been staked, decapitated and / or killed by Captain America, Union Jack, the Invaders, Namor, a different Union Jack, and an english army officer. He is also a professor at the Latverian School of Science.
Death Adder killed M.O.D.O.K., was shot and killed by the Scourge of the Underworld, was resurrected and killed Tigra, SURVIVED a fight with the Punisher and was then killed by Venom.
For the record, most of the people I have drawn I have only a passing familiarity with, and all the stories I tell about them I get from wikipedia.