Jean Bart is a pirate originally introduced as a slave in Saint Roswald's Pirate Captain Collection. Named after the real-life pirate Jean Bart, his fate changed after Luffy's disruptive actions at the Human Auctioning House. Trafalgar Law freed him during the chaos and offered him a position within his crew. Freed from his Tenryuubito master, Jean Bart accepted Law's offer and became part of the Heart Pirates.
During the turmoil at the Auction House, Law removed Jean Bart's collar, recognizing his potential and offering him a place among the Heart Pirates. Moved by the recognition and the opportunity to reclaim his identity, Jean Bart agreed to join Law. As they fought against the Marines together, Jean Bart expressed his gratitude to Law for freeing him. Law responded by sharing the credit with Luffy, stating that without Luffy's reckless actions, Jean Bart would still be enslaved.
(Source: One Piece Wikia)
