User blog comment:Roranoa zoro/caribou ??/@comment-1908942-20110110233121

It's still way early in the game to truly be accurate in guessing, but that's never stopped me before:

If the final villain of the Arc is human, then it's fairly easy to say Caribou will be freed by the unknowing Mermaids and try to screw over the Straw Hats. In the end, he'll serve as a mid-Arc appetizer for Luffy (Or Zoro if he has Haki). Or maybe even this older Merman prince as he seems at least aware of Haki.

If this Jones guy is the villain, it's harder to say. Personally, I think if that is the case, he'll start a fight with him, and be beaten to show off his power. Or, if humans joining wasn't just restricted to Luffy, may join, but still lose to Luffy.