The Bounties Pirates' strength lies in its captains, Bounty and Prize. The two ParameciaDevil Fruit users earned the attention of Kaidou, one of the Four Emperors and the captain of the Beasts Pirates, and they were considered a credible threat by the kings at Levely. Bounty has earned a bounty of 1,000,000,000, one of the highest bounties in the series (and the highest for a non-canon character), and Prize has earned a bounty of 800,000,000.
Bounty wanted to earn the highest bounty in history of 100,000,000,000, so he and Prize devised a plan to kill all the kings attending Levely with poison gas bombs developed by Caesar Clown. They found Caesar, and Prize stole his heart with his abilities to force him to do their bidding.
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When Caesar was kidnapped by Igaram Jr., the Bounties Pirates pursued him. This led them to the Straw Hat Pirates, and after fighting the opposing crew, Prize stole Igaram Jr.'s heart and retrieved Caesar. The crew attacked the Thousand Sunny before leaving for Levely. They sent a note to Mary Geoise announcing their attentions, causing the kings to panic and flee to an evacuation ship.
After Caesar finished making the bombs, the Straw Hat Pirates followed and destroyed the crew's cannons. Bounty was defeated by Monkey D. Luffy, Roronoa Zoro, and Sanji, but Prize threw a poison gas bomb using his abilities at the evacuation ship. The bomb was to make contact with the ship in ten minutes. Bounty got up to protect his brother, and members of Buggy's Delivery assisted. The Straw Hat Pirates, Duval, Crocodile, and Daz Bones tried to knock Prize out before the ten minutes ran out to stop the bomb's delivery. With one minute to spare, Luffy activated Gear 4: Boundman and pummeled Bounty, and though Bounty did not fall, he was moved out of Luffy's way, allowing him to attack and knock out Prize. The bomb stopped short and fell into the ocean before hitting the kings' evacuation ship.