Luffy is Uranus
Or rather, he’s another Uranus, with the first and only one having been the Leader. I talked earlier about what power Uranus was capable of. I believe that the Leader of the Ancient Kingdom possessed the same power that Luffy currently possesses; the power that Mihawk himself praised as being “the most dangerous ability in this entire ocean”.
Uranus, or rather Luffy, possesses the power to turn foes and distant people into allies willing to sacrifice their lives for his ideals. We’ve seen this multiple times in the past, and it culminated itself in the formation of the Grand Fleet in Dressrosa.
Think about it. Pluton is a large ship capable of massive destruction. Poseidon is a mermaid able to talk to and command Sea Kings. You’ve got a war ship and massive beasts as two weapons of mass destruction. All that’s really left is an army, which is what Uranus is. And similar to how Poseidon turned out to be a living thing, Uranus will turn out to be none other than Luffy.
“You’re not the man Roger is waiting for”
Is what Whitebeard told Blackbeard before he died to him. The major difference between Luffy and Blackbeard, other than the fact that one is good and one is evil, is the fact that Luffy possesses the one ability able to take the World Government down: His heart and ideals are so pure that even foes eventually get moved by them and ally themselves with him. Blackbeard, on the other hand, only knows how to backstab, kill and use people until he got what he needed. He’s not the man Roger or any of the people of the D clan are waiting for because no matter how strong he gets or how many Devil Fruits he amasses, he doesn’t have an army that believes in his ideals, an army ready to sacrifice itself in the blink of an eye to save his life, and he isn’t willing to do the same for them either, unlike Luffy who’s shown multiple times how far he’d go to save a friend.