The Battle of Carteneau is a conflict in Final Fantasy XIV fought between the Allied Forces of Eorzea, comprising of the Grand Companies of Ul'dah, Gridania and Limsa Lominsa against the forces of the VIIth Imperial Legion of the Garlean Empire.
The Allied Forces were led by General Raubahn Aldynn of the Immortal Flames, Elder Seedseer Kan-E-Senna of the Twin Adders and Admiral Merlwyb Bloefhiswyn of the Maelstrom. On the other side, the remnants of the VIIth Imperial Legion fought following the will of their late general, Nael van Darnus. The Battle of Carteneau was the final battle of the Sixth Astral Era, and the result of this battle plunged Eorzea into the Seventh Umbral Era.
Because of the maniacal schemes of Nael van Darnus, the crimson moon Dalamud was set to crash into Eorzea. Though adventurers defeated Nael, Dalamud could no longer be stopped. The Archon, Louisoix Leveilleur, sought to summon the The Twelve, deities of great power, to stop Dalamud's descent. He had the adventurers pray at the Deity Stones scattered across the land to prepare for the upcoming effort, but the deities could only truly be summoned in a place with high aetherial concentration.
The Battle of Carteneau, taking place in the near center of Eorzea within Mor Dhona, began when the main host of the Eorzean Alliance clashed with the main host of the VIIth Imperial legion. Prior to and during this conflict, the adventurers of Eorzea were tasked with hindering remnants of the legion that hadn't yet joined the main Imperial host.
The Empire made liberal use of their advanced technology, and attacked the Allied Forces with gunfire and magitek armor. The Allies responded with a barrage of elemental spells cast by their Black Mages and Thaumaturges. In response to the Garleans' ranged firearms, Bards and Archers took to ranged battle.
As the battle raged on, Dalamud drew closer and closer. Mid-battle, the satellite fractured, dropping a spire-like object from its surface. Looking on in awe and terror, both sides watched helplessly as Dalamud, the moon they had been observing for years, broke apart before their very eyes, revealing something nobody, save Nael van Darnus, could have foreseen.
End of an Era
Having been sealed within Dalamud since the time of the Allagan Empire, the Elder Primal Bahamut emerged from his prison. With an almighty roar, he shattered his crimson prison, sending debris all over the continent. Enraged after eons of duress, Bahamut unleashed his wrath upon the realm in the form of his devastating Gigaflare, spewing forth endless fire and destruction. Louisoix conjured a barrier to protect what remained of the Eorzean Alliance, and began the arcane rite to channel the power of the Twelve and focused it into rebinding Bahamut. A pillar of light erupted from Gridania. Then another from Ul'dah, then Limsa Lominsa. All over Eorzea, the Deity Stones sent up enormous pillars of blue light, forming a circle around Mor Dhona, and Bahamut.
Rekindled with the hope of sealing Bahamut, Louisoix summoned a pillar of light from the Deity stone beneath him. These lights became magical spikes that briefly floated around Bahamut before shooting into the sky and back down towards the dragon. With a roar of anger, Bahamut shielded himself with his wings. The spires connected, and began enveloping Bahamut in a new Dalamud-like prison. All of Eorzea became a huge sealing spell, with glyphs of the Twelve appearing in a circle around the newly-forming prison. The symbols of the Twelve began to rise, indicating the summoning of the Deities and the near completion of the sealing spell.
Bahamut broke the sealing spell and gathered his power to unleash his Teraflare. All hope for the battle now lost, Louisoix, knowing of the scope of the attack Bahamut was about to make, channeled the power of Althyk the Keeper, god of space and time. He sent the surviving heroes into the Rift where they were to remain untouched by the passing of the seasons until it was again safe to emerge and continue their struggle to forge Eorzea's future. As the last living person in Carteneau, Louisoix accepted what fate had for him.
Flames of Truth
Louisoix received a vision from the Twelve in the form of the light spears that attempted to seal Bahamut, giving Louisoix the remaining aether from the attempted summoning and he was granted incredible powers. Taking to the skies, Louisoix flew into Bahamut's Teraflare, creating a barrier to repel the massive fireball. Bahamut fired a burst at Louisoix before flying down to face his Elezen adversary. The Elder Primal bore down on Louisoix, shattering the aetheric barrier.
Louisoix harnessed the mass amounts of aether in the area. Combined with the prayers of thousands of Eorzeans, he took on the form of the primal Phoenix. In the aetheric cloak of Phoenix, Louisoix ascended through Bahamut's Teraflare, pushing the Elder Primal out the other side while crystallizing the massive Teraflare orb. Bahamut's chest was pierced as Louisoix pushed out the other side. Returned to his mortal form and his aether spent, Louisoix crystallized and shattered, Bahamut doing the same shortly after. The crystallized Teraflare shattered, raining destruction down upon Mor Dhona and leveling the southern half of the area.
Eorzea was forever changed by Bahamut's rampage after the battle, though no one knew how the primal was defeated. The devastation in the Carteneau Flats had exposed numerous Allagan ruins, including a buried superweapon known as Omega, which became contested by the city-states of Eorzea. To resolve this conflict without fracturing the alliance, the Grand Companies agreed to a civilized conflict within Carteneau. This did little to stop the schemes of Ul'dahn Monetarists seeking the weapon, who incited unrest in the city-state, culminating with the Ul'dahn Revolution.
Despite his defeat, Bahamut lived on thanks to the machinations of the Binding Coil of Bahamut, remnants of Dalamud that would ensure the Elder Primal's resurrection. Through Allagan technology and the entire race of Meracydian Dragons in stasis constantly praying for Bahamut's salvation, he could not be permanently defeated. His will reached out and enslaved Louisoix's spirit to serve him as both his protector and as the primal Phoenix. When Louisoix's grandchildren, Alphinaud and Alisaie Leveilleur, entered the Binding Coil they learned the true end of the Battle of Carteneau, but decided to not unveil this to the public.
Following the death of Varis zos Galvus at the hands of his son Zenos yae Galvus, the VIIth, having changed leadership multiple times since the death of van Darnus, ends up under the leadership of Valens van Varro. They continue the Ultima Weapon project following Gaius Baelsar's defection from the Empire, developing several prototypes and basing them in the puppet state of Werlyt. One of these prototypes, the Ruby Weapon, was deployed to the Ghimlyt Dark to break the stalemate with the Eorzean Alliance, and was destroyed by the Warrior of Light at Gaius's request. The imperial-controlled town of Terncliff was later liberated from the VIIth after the Warrior of Light destroyed the Sapphire Weapon.
Behind the scenes
The Final Fantasy XIV servers were temporarily shut down at the conclusion of the battle. Version 2.0, A Realm Reborn, saw the adventurers of the battle return from the Void they were placed in by Louisoix, into Eorzea once more. The Battle of Carteneau thus runs concurrently with the final minutes of the Final Fantasy XIV servers. Five minutes before the servers were shut down, players received a message informing they had lost contact with the main host.
Much of the 1.0 storyline focused on Nael van Darnus and his desire to bring Dalamud down upon Eorzea. As the players progressed through the storyline, it was revealed that Darnus was slowly losing his grip on sanity, and that Dalamud, or rather Bahamut, was influencing him from afar. Darnus began referring to Dalamud as "Him" although the players did not yet know that this is Bahamut.