Vlad Tepes was far from a legend and he actually lived and ruled his lands. The man was truly hungry for human blood and he had discovered a way to become something close to an immortal being with it. We believed that a species like his would be extremely dangerous to the world and there would be no humans left if more men and women became like Vlad. Once we knew that he started to build an army of immortals we had to pull the plug on his plans.
We had to lock him inside a dungeon and make sure that he was weak enough from the lack of blood consumption. Then we burned him and buried his remains deep underwater. The immortality he had was only possible because of the blood consumption, once that was taken he became a mere mortal again. This is the closest thing to a vampire that ever existed.