Morbius, the Living Vampire
He was a famous biochemist who was suffering from a debilitating blood disease, and injected himself with vampire bat DNA in hopes of curing himself, but became a living vampire. Despite being introduced as an antagonist of a few heroes, in some versions of the universe, he is an anti-hero who has worked with Spider-Man and Blade, and was a member of the Legion of Monsters and the Midnight Sons.