User blog comment:Observer Supreme/The Gorosei's Role/@comment-24850639-20161213160047

Yeah its definitely the Celestial Dragons that actually rule the world, the Gorosei to me have always come off as proxies for the political and military stuff that they don't want to be bothered with. We haven't seen them directly interact with each other, but I'm almost positive that the CDs would look down on them just like they do everyone else. The CDs probably wouldn't enjoy the fat, lavish, and luxurious life they live if they had to put on their big boy pants and make decisions that affect the world as a whole on a regular basis. On another note though, I don't think Sakazuki/Akainu would be so snippy with the Gorosei if they truly had the power to make life difficult for him. While I think they do have SOME military clout in the form of Cipher Pol, that main responsibility of the marines probably still goes to Kong.

So to sum it up, I think both the Marines and WG ultimately work for the Celestial Dragons, but the Gorosei have been appointed to handle the WG's political agenda, while the Marines handle the military might. The Marines are technically considered part of the WG, but have their own command structure. Cipher Pol probably has its own structure as well, and for the most part report to the Gorosei. CP-0 specifically reports directly to the CDs.