Good thread. I disagree with it, but good thread.
Okay, so we get the main theme of the series from Roger in chapter 100.
“These things cannot be stopped.
An inherited strength of will
one’s dreams
the ebb and flow of the ages
as long as people hunger for freedom...
...these things will exist”
The drive for freedom being what pushes mankind towards achieving dreams, and a mutual destiny (not in a necessarily prophetic sense but in the sense of the overall purpose of mankind.)
Is Justice, as a concept, opposed to freedom? No. Control, slavery, oppression, is opposed to freedom. Justice is its own thing entirely. People (pirates and marines alike) have their own sense of what justice is. That’s why you can have a free Marine like Garp, and an authoritarian, dictatorial pirate like Kaido. Even Luffy has his own sense of what is ”just”- there’s no such things as the sins of the father, nobody deserves to be laughed at after they die, so on. It’s no coincidence that the big justice speech in the series was delivered, in the middle of a war between pirate and marine, by a pirate who himself is a despotic Celestial Dragon king. Themes aren’t clear-cut and divided between Pirate and Marine. Kuzan’s quest for justice is involving him leaving the Marines, Smoker’s plotline is all about questioning what is just and him teaming up with Luffy time and time again.
The opponents of freedom aren’t the World Gov, per se. Note what Koala said before the Reverie:
”You’re fighting the World Government for the sake of the fish-men. Don’t you feel at all conflicted about the Ryugu Kingdom taking part in the Reverie?”
”Not at all, Betty! Our true foe isn’t actually the World Government, it’s the Celestial Dragons who control it.”
The Celestial Dragons aren’t even slightly interested in what is just or not, because they, for the most part, consider themselves gods. I doubt Charloss could even spell justice.
As for the question of final opponent- how exactly does that rule out a pirate?
The theme, as you say, is freedom. Now, there’s two ways you can approach an enemy that reflects that. You can go one who does not believe in freedom, and exemplifies slavery- the World Gov.
Or you can go the other way- what abuses can the concept of unfettered freedom bring about? That’s how we get to Blackbeard, a man who lives completely free, follows his dreams, has inherited Rock’s will, is pushing mankind in an inexorable tide towards a world of anarchy. Blackbeard lives free as a bird. That’s why he lies, cheats, murders and wrecks his way through the world. What if a man like that was to then take control of the world? That’s final villain material.
Take note of what we know from Rocks.
He was a D
He gathered a collection of incredibly powerful, dangerous pirates under his command
He operated out of Pirate Island
He went after the secrets of the world
He wanted to be King of the World
In the end, both Pirate and Marine had to team up, defending Celestial Dragons in the process, to defeat him, Roger’s greatest enemy.
Now Blackbeard
Is a D
Gathered a collection of powerful, dangerous pirates (Impel Down Raid)
Operates out of Pirate Island
Is interested in researching the ancient history of the world
Named his flag ship after Rocks
Wants to be Pirate King, declares it his era
Everything points towards Blackbeard wanting to do what Rocks did. If he can get a way to put his fat ass on the throne to declare himself King of the World, with his first policy being that there are no laws whatsoever, then you’ve got a final villain. If Rocks can be a threat that manages to unite Roger, the Marines and the Celestial Dragons, you can bet Blackbeard will go one better.