Few One Piece characters are as vile as Marshall D. Teach, or Captain Blackbeard. Starting out as a member of Whitebeard's crew, Teach betrayed his surrogate father and siblings when he killed Thatch to steal the powerful Dark-Dark Fruit, a Logia type. Years later, Blackbeard captured Portgas D. Ace and handed him to the World Government to gain the status of a Warlord. Blackbeard did all this so he could cause a war that would allow him to acquire the crew he wanted, kill Whitebeard and steal Whitebeard's own Devil Fruit powers, but how can Blackbeard have two Devil Fruits?
Source：https://www.cbr.com/one-piece-blackbeard-multiple-devil-fruits-theories/
