The war against Cocoon—it was inevitable. The army of Gran Pulse was annihilated by the overwhelming power of the fal'Cie. Countless lives were lost.
Several hundred years ago, the armies of Pulse attempted to invade Cocoon in a conflict known today as the War of Transgression. The Sanctum's fal'Cie were able to repel the lowerworld forces before they breached Cocoon's interior, but not before they managed to seriously damage areas lying near the world's outer rim.
Details surrounding the clash remain shrouded in mystery, but the government's swift and decisive response to this violent Pulsian transgression minimized casualties and greatly boosted public faith in both the Sanctum and their fal'Cie.
Fragment of Invincibility
The War of Transgression that pitted Cocoon against Pulse took place 700 years before the catastrophe. The common wisdom on Cocoon is that the war was sparked by a Pulse invasion; however, Pulse records claim that the culprit was a 'demon from Cocoon.' Historians remain divided to this day.
The people of Pulse had always feared invasion from the sky, and made preparations accordingly. These included 'immortals', war machines of immense strength and durability that were able to fight fal'Cie even when half-destroyed. The ancient weapons were designed for a defensive war on the ground, not offensive airborne assaults. Some historians claim that this proves it was Cocoon that instigated the war.
Cocoon was created by the deity Lindzei, the Maker of the Cocoon fal'Cie, who stole numerous resources from Gran Pulse. The Cocoon fal'Cie lured Pulsians to Cocoon with sweet promises of paradise, giving those who remained the impression that Cocoon was a source of evil that must be destroyed. Similarly, the inhabitants of Cocoon were made to believe that Gran Pulse was a primal, hellish world filled with unknown terrors. Cocoon's plundering of Pulse's resources ignited the wrath of the Pulse fal'Cie Anima who set on to wage war on the floating world.
The Cocoon fal'Cie wish for Cocoon's destruction so that the expiring human souls from the countless extinguished lives would reveal Etro's gate, the gateway to the unseen realm. The fal'Cie thus hope to call their Maker back into the world of the living so that the world could be reborn. Unable to destroy Cocoon themselves because they have been crafted for the purpose of its maintenance, the fal'Cie Barthandelus plans to have Pulse l'Cie destroy Orphan, the fal'Cie that sustains Cocoon by lending its power to all the rest of the fal'Cie.
Anima chose two Pulse l'Cie to destroy Cocoon from the northern village of Oerba: Oerba Yun Fang and Oerba Dia Vanille. Their Focus is to destroy Cocoon by transforming into a being known as Ragnarok. Due to Vanille's fear of the beast's power, she ran off and left Fang to carry out the task on her own.
Fang's incomplete Ragnarok cracked Cocoon's outer shell. The goddess Etro, knowing that Cocoon's destruction and the resulting deaths would disrupt the natural order, transformed both Fang and Vanille into crystals before they could complete their Focus.
Cocoon suffered considerable damage during the war: its shell was cracked open and the Sanctum fal'Cie had to salvage components from Pulse to mend it. The War of Transgression spread fear of Pulse among the citizens of Cocoon, which lasts for centuries. During modern times, the Pompa Sancta parade in the theme park of Nautilus enacts the war from Cocoon's perspective, telling how brave Sanctum l'Cie stopped Ragnarok's rampage. The Pulsian recollection of the war is recorded by survivors in Oerba in a Cie'th Stone, which is left as a relic when the population dies out.
Almost the entire human population of Pulse was wiped out, with survivors being outnumbered by the monsters patrolling the underworld. Exactly how this happened is unknown, but it was likely a combination of many things. The Cie'th Stones mention Pulse fal'Cie turning people into l'Cie with vague Foci, and Pulsian ruins are left swarming with Cie'th. Anima was the protector of Oerba, but after the war, the Pulse Vestige containing Anima and Vanille and Fang's crystal forms was taken into Cocoon by Barthandelus, leaving Oerba defenseless.
Behind the scenes
In Final Fantasy XIII-2, Hope says that records describing the War of Transgression were found in an Oracle Drive. He confirms Serah's recollection of what would appear to be a commonly known historical date (at least by grade school teachers), with the war occurring 680 years before the catastrophe (the events of Final Fantasy XIII). A Fragment entry (Fragment of Invincibility) from Archylte Steppe ??? AF in Final Fantasy XIII-2 makes the same time frame seven hundred years, and the Final Fantasy XIII Scenario Ultimania suggests the war broke out approximately 600 years before.
- Quote:KEYWORD War of Transgression - The war broke out approximately 600 years ago (666 years ago according to one theory). (KEYWORD 黙示戦争 - 約600年前に（一説では666年前）に勃発した。) Final Fantasy XIII Scenario Ultimania. p.055.