4. Angelus (Buffyverse)
When the heroic vampire Angel loses his soul, he becomes his evil alter-ego Angelus. Angelus was the most famed and sadistic vampire in history in the Buffyverse. He waded through Europe relentlessly, torturing and killing humans like they were nothing and enjoying every second of it. As far as being a foe for Batman is concerned, Angelus' threat is twofold: First, he's a physical threat, given his vampiric nature grants him a level of superhuman strength, speed and durability, while he is also a skilled fighter (though that is more Angel's forte). Second, he is brilliant at psychological warfare - getting in to his opponents' minds. If he had Spike, Darla and Drusilla in tow, things could get even worse for Batman. Wearing his usual all-black attire and having to spend his time in the shadows gives him a distinct similarity to the dark knight and for that reason, as well as those above, he would make a great Batman villain.