Elbaph made it clear that it's about Someone (Either Luffy or Usopp or Loki or Together) convincing Giants to Fight,
Convince them to Defend their Homes? Ofc not, such thing doesn't need Persuasion, it's obviously to Fight "Outside" Elbaph,
Who are They gonna Attack? Obviously World Government, in other words, Mary Geoise.
Loki's Special Bounty + Carmel's Teachings + How Oimo & Kashii were Tricked + Holy Knights ... etc
It's clear that WG are gonna be the Target of Elbaph's Rage,
It's just like Water 7, it starts in Elbaph, but They will then set Course to Mary Geoise (Dunno what Transportation They gonna use),
Holy Knights will Fall with Mary Geoise just like CP-9 Fell with Enies Lobby,
This is the War that's gonna make Marineford look Cute,