Alucard is one of the original vampires, unlike the new breed that has sprung up in England. Alucard's occupation is rather different in that he hunts his own kind. He justifies killing vampires because these vampires he's hunting down are not vampires but just some cheap imitations created by science. He views these beings even lower then humans. He fights for the Hellsing Organization and serves his master, Sir Integral Wingates Hellsing.
Alucard is virtually indestructible. He can get shot to pieces only to regenerate, be stabbed by hundreds of blessed blades, and get shot in the head by silver bullets and still live. He even got his head chopped off in episode 8 and still lived! Alucard is one vampire not to mess with.
Yes, the name "Alucard" is actually "Dracula" spelled backwards, but we don't really know who Alucard is. The series does shed some light on who Alucard might be, and most people believe he is Vlad the Impaler (also known as Dracula) who was notorious for impaling his victims on poles. However, there is a possibility that this might not be the case....
Video preview: