Marshall D. Teach, also known as Blackbeard, is a notorious pirate in the world of One Piece. He is the captain of the Blackbeard Pirates and one of the Four Emperors of the Sea, making him one of the most powerful pirates. Teach is a former member of the Whitebeard Pirates, but his ambition and desire for power led him to betray them. He is known for his cunning and ruthless nature, having acquired the power of the Yami Yami no Mi, a Logia-type Devil Fruit that allows him to control darkness. Teach is a central antagonist in the series, playing a critical role in the unfolding events of the One Piece world.