I think, it is the influence that one has on the pirate world. The Yonkou, by what we know, are all heavily involved with a certain market that THEY are running and the WG doesn’t hold leverage over – this is NOT accounting the fact that just one Emperor may well have the potential to wipe the entire marine force from the face of the planet.
Big Mam: markedly invests her protection in return for instalments of something specific (sweets so far.. hope it gets more interesting as the story progresses) – a protection policy. If the quota is not met, she will destroy the place of contract. This cruel method of bargaining is what makes her pirate trade successful – using fear to get results.
Kaidou: is in control of the black market, formerly administered by the, now defeated, Joker. SMILE aside, the black market frequently dealt in with the weapons trade to keep wars among countries active for business. Whoever funds both sides of the war may expect the greatest income in profit. Sadly, that statement holds true in real life too.. That is Kaidou’s market. He’s a master industrialist with a terrible temper.
Blackbeard: is currently growing and strengthening his forces.
Not to mention that the Yonkou war with each other constantly over territory in the NW to tip the power struggle to their favour.
Now, as seen in the images above, Luffy has been offered a number of 5600 pirates to serve with the Straw Hats as the flag ship. Not only that, he will also have the backing of a pirate crew that was once feared across the globe – the Giant Pirate Crew.
The Straw Hat Pirates will most certainly catch a position of influence for themselves if they had followers that numbered in that many. In fact, if something like this were to happen.. Who else would you imagine joining this new mainframe that is led by a member of the Worst Generation? (If it’s going to be led by Luffy)
My prediction is that Luffy’s character will compel him to reply in the fashion of:
“Eh, seems like a bother. I don’t care what you do, just do what you want.”
Luffy wanted to captain his own crew. But he never wanted an army. This is where Law’s wits come in.. Law sees, not only an opportunity for higher protection and easier access into enemy territory, but a sure-fire way to counter against Kaidou in battle. (Big Mam is Luffy’s enemy, Law has nothing to do with her)
What could be better than 1 member of the Worst Generation governing the world’s most powerful pirate armada? That’s right. 2 Members of the Worst Generation!
Luffy is in control, gives the orders and makes the decisions. Law administers the troops, sends out missions and ensures a healthy information mainframe between all crews. His underground alias becomes ‘Corazon’ – in respect to his former parent-figure and the fact that it says so at the back of his robe might indicate foreshadowing.
A market begins to brew, a market that offers protection in exchange for hospitality, banquets and doctoring for every instance that an allianced crew or member arrives at said place of contract. Luffy’s name, with the gratitude that comes from saving said villages, cities etc. begins to spread like a tempest across the ocean (and is well received by citizens of Dress Rosa, Arabasta, Fishman Island and, soon to be, Kano)
Kaidou and Big Mam hate Luffy. This hatred is to turn into gang wars at sea, you see a pirate member or crew with the enemy alliance, you kill them.. You kill their market, you kill their influence.
Not to say, movements such as the Revolutionary Army may very well consider joining this alliance for the benefit of their own organisations, or at least the countries that they are trying to protect/and or attack.
*Theory by TheSey