Interesting.. What do you mean by fighting for Time..
Sky Island Story was about Shandia landing in Skypiea, which Triggered War between Shandians & Skypieans,
Both were Right, cuz Shandia is indeed Shandians Home but at same time it's inside Skypieans Home, so They also have a say in it now,
I always believed that Ancient War was about similar Conflict, meaning both Sides were Right,
You can see this in every Kingdom visited by SHs, always Two Sides Fighting, but Real Villains are those who are Outsiders (Like Birkans),
But what if that War wasn't about "This Land belongs to me", and instead about "This Timeline belongs to me",
Imagine if there was a Main Timeline & then suddenly a Piece of another Timeline appeared in it, replacing a Segment of it,
It's like in Sky Island, you can walk in Clouds & then suddenly you can reach Vearth & then it's Clouds again,
Instead in this WG Story, it's about History following it's normal timeline & chain of events & then suddenly the Story is changed out of nowhere & it remains like that for a certain Period and then goes back to normal
This Period is clearly none other than "Void Century" & both Sides are Correct, because One Side will say "This Era belongs to our Timeline" while Second Side will say "This Era is now Part of our Main Timeline Continuity", both have a Claim for it, it's also why WG desperately wanna hide Truth about it, because it's not about a War or Crimes or Place ... etc but what can really make People go crazy is learning that They actually have a Second Scenario in their Life, that's something Priceless for them
But just like Upper Yard or Onigashima, that New Piece is claimed by Main Villain, hence why that Period became known as Void Century, because it was taken by Final Villain, and just like Enel's Dream was to instead Conquer "Endless Vearth", this Final Villain's Dream doesn't just want Void Century, He wants entire 2nd Timeline, We can call it Endless Void (This is why Oda in SBS showed us Two Timelines for Future SHs)
This also matches with how Villains were made, if you look closely you can notice that Luffy became Water Luffy against Villain who stole Water (Jinbe), and became Afro Luffy against Villain who stole Nakama (Brook), and became Golden Luffy against Villain who stole Gold (Nami), and Nightmare Luffy resembles Chopper, and Champion Luffy resembles Franky & Samurai Luffy resembles Zoro ... etc
Two Remaining are a Villain who Steals Plants (Usopp) + Villain who Steals History (Robin),
We already seen this Villain who lives in Kingdom where there is Sunlight Tree Eve, their Arc is connected to Kingdom with Adam Tree, and their Personal Room is full of Plants & Flowers, that's clearly Imu
Then it's time for Villain who stole History itself, He is literally the Narrator himself!
And in Current "Bad" Timeline, Blackbeard is the actual Main Character, Luffy must Defeat FV + BB & Reverse that,
In other words, Luffy will fix the Ending of this Story, but this entire Adventure won't be part of Timeline anymore,
People will debate on whether it was a Dream or Lies or Fake Tale ... etc
Or as Zoro summarized it "Nothing Happened"!
This is why Roger described entire Journey as "Let's turn the World upside down",
Meaning it's Same Coin (Same World) but Two Different Sides (Two Stories), hence the Title "One Piece".
