Kiba was the former captain of the Fanged Toad Pirates until he lost to Foxy at the Davy Back Fight and joined his crew. The former captain has crossed out the Jolly Roger on his hat, further signifying his defection from his old crew.
Later, in an anime filler, Kiba took over the Foxy Pirates after Foxy lost the last event of the Davy Back Fight, and refused to allow Foxy back. After a fight against him, and the Straw Hat Pirates, he finally decided to let Foxy rejoined his crew.
First Appearance: Chapter 306; Episode 208
Source: