He was! If we assume Davy Jones was the in the same time period that means he followed Joyboy in becoming a pirate. Maybe the One Piece is something that gives someone dominion over the world that had to be stolen (why pirates are so pivotal to finding it) and Davy and Imu used it to become “King of the World”. Blackbeard wants “the world”, same as Rocks, and Luffy wants to become the pirate king to become the most free and since Joyboy was Nika I think we can guess he wanted the same thing as well.