Was Blackbeard as fearsome as the legend suggests?
He was extremely effective at appearing fearsome, which was the point — and the striking thing about Edward Teach is that there is no confirmed record of him killing anyone before the battle in which he died.
What he actually did. Operating for roughly two years, from about 1716 to 1718, he commanded a captured French slave ship renamed Queen Anne's Revenge, blockaded Charleston harbour, and took a large number of vessels — almost all of them without a fight.
The theatre was the strategy. He cultivated an image deliberately: an enormous black beard braided and tied with ribbons, and — according to a contemporary account — slow-burning fuses tucked under his hat, wreathing his head in smoke during an engagement.
Why this was rational rather than vanity. A crew that surrenders immediately costs a pirate nothing: no casualties, no damage to the prize, no lengthy pursuit. Terror was a means of avoiding combat, not of pursuing it. A reputation that made resistance seem futile was worth more than any weapon, and pirates generally understood this.
The counter-evidence to his ferocity is notable: accounts describe him releasing prisoners, and the Charleston blockade ended with a ransom demand — for a chest of medicine — after which the hostages were freed.
He did accept a royal pardon, briefly settled in North Carolina, and returned to piracy.
His death was genuinely dramatic, and this part is well documented: killed in 1718 at Ocracoke in a boarding action by a force sent by the Governor of Virginia, reportedly sustaining many wounds before falling, with his head taken as proof.
Why the legend grew so large. A popular general history of pirates published a few years later — of disputed authorship — established much of the mythology and was hugely influential.
The buried-treasure element is essentially fictional, popularised by later literature. Pirates spent their takings.
The wreck of Queen Anne's Revenge was located off North Carolina in 1996, and excavation continues.