Peterman

Peterman (ピーターマン, Pītāman) is the head of a kidnapping gang called the Hound Pets, located at Sabaody Archipelago. He is informed by the same bounty hunters that attacked the Straw Hat Pirates before that Keimi, a mermaid, is at Sabaody Park. He then arranges a deal of 10% of her final selling price to the bounty hunters and goes leaves to kidnap her.

He later takes her to the Human Auctioning House, to come back after she's sold for his share of the money. He never gets the chance however as the Straw Hats managed to rescue her and Duval gives him a deserved beating for his actions and take Keimi's bag back for her.