While the answer to this question is a matter of opinion, many people believe Blackbeard was the most feared pirate in history. He was said to practice in voodoo and the black arts and he was quite cruel. He supposedly lit candles or hemp in his long braided beard to create a cloud of smoke and he brandished his weapons with both hand, simply choosing from pistols, daggers, and knives attached to his chest.
Legend has it that he offered his 16 year old wife to his crew and let them ravage her while he watched. He worked at his fearsome reputation so much that it is said he actually never had to kill anyone, but he was still cruel, once shooting a man in the knee under the table while they were playing cards.