User blog comment:Juracuille/The Last Strawhats' Enemy/@comment-2117107-20100628145442

Yeah, true... I was thinking of Coby becoming a huge enemy... Just like Monkey D. Garp and Gol D. Roger were enemies, yet also friends as well. But this will be way further into the future, as Coby is still too weak to face Luffy.

Blackbeard Pirates will probably be a huge threat, though not the last enemy, as I reckon as soon as Luffy is strong enough, he will try to revenge Ace.

Overall, I reckon the last enemy will just be the Marines as a whole... They are against piracy after all.