User blog comment:Rhysno1/If Luffy was captured by the Marines, who would come to his rescue?/@comment-1812363-20101014195144

If I had to think of one person that would come after him harder than all of the others, I'd have to say Nico Robin, returning the favor from Enies Lobby.

Besides that, I'd have to say that more or less everyone he's met would come to either A. help him, or B. see him die for themselves.