Who is Bad of Esgaroth? How is he able to kill Smaug?

Bard, the grim-voiced, grim-faced man, is willing to challenge Snaug and he has help from a messenger bird, called a thrush. The thrush relays information that Bilbo discovered while in Smaug's lair: the hollow of Smaug's left breast is not plated with his red-gold armor. When Bard strikes this spot, Smaug falls dead, his massive body crushing the city of Esgaroth. The survivors seek Bard as their new king but Bard provisionally declines the offer, though he intends to establish his own city. As the news of Smaug's death spreads, various groups advance towards the mountain‹for there is treasure to be had. Also check out,

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