User blog comment:Roranoa zoro/caribou ??/@comment-3242083-20110106140702

Caribou only serves as a comparison for the "new" confident and matured strawhats.

Think about it. He is in the exact same position the strawhats were in... 2 years ago. A naive and arrogant supernova, believing the new world is just waiting for him to get roughed up. What happened? His crew got crushed, not even reaching the entrance of the new world (fishman island).

Now lets have a look at the strawhats. They solved every obstacle with ease and turned one of the most dangerous enemies (the kraken) into an ally. A volcanic eruption, threatening to annihilate the ship? No problem. Superior fishmen trying to stop them? No problem.

And then they have Caribou on the ship, who does nothing else but looking shocked and afraid of the sheer confidence and power of Luffy & Co.

One piece is dependent on characters like him, else how can you tell how awesome or strong the maincharacters are (without a good comparison)? Similar to Usopp, who serves as a contrast to the monster trio.