User blog comment:Fintin/Final Enemy/@comment-5962458-20140322191324

You forgot about a certain fellow...the one who entertains children parties in his free time.

Jokes aside, I think the world government will be the final enemy, because otherwise one piece would have no meaning.

What I mean is, that in order to become pirate king and get one piece, you have to go to Raftel. Blackbeard wants to become pirate king, too, so it is pretty obvious that Luffy will fight him right before getting to Raftel or on it. After that, Luffy will get One piece and (unless it is a giant dildo) he will have to use it to restore the world in its right place according to the crap the ancients wrote on the stones. In doing that his biggest rival will be the WG.