Operation Archon is the major showdown at the end of Final Fantasy XIV: A Realm Reborn It was the Eorzean Alliance's response to Gaius van Baelsar, the Black Wolf, issuing an ultimatum to the city-states and beast-tribes with his trump card: The Ultima Weapon. Operation Archon was drafted up by the Scions of the Seventh Dawn as a multi-stage plan to cripple the XIVth Imperial Legion and destroy the Ultima Weapon inside Gaius' stronghold.
In-game, Operation Archon composes the final segment of the V2.0 Main Scenario quests. The player is mainly involved in eliminating Rhitahtyn sas Arvina at Cape Westwind, and directly infiltrating Castrum Meridanum and The Praetorium. The remaining battles occur off-screen.
In order to cut off support from sea, the Aethernet Gate at Cape Westwind had to be captured while the Lominsan navy would encircle Castrum Marinum. Rhitahtyn sas Arvina, Gaius' most trusted and skilled commander, was placed in command of the base, and was personally at the Aethernet gate. The Warrior of Light confronted and slew Rhitahtyn after a fierce battle, dealing a blow to the XIV Legion's morale, while Castrum Marinum was successfully encircled.
With Cape Westwind and Castrim Marinum gone, the next part was cutting off the phantom train supply lines to Castrum Oriens and Ala Mhigo. The Order of the Twin Adder laid siege to Castrum Centri.
The final step was for the Immortal Flames to march through Raubahn's Push and pin down Gaius in his stronghold. The barrier in Castrum Meridianum was the only obstacle left to confronting the enemy. Cid nan Garlond and the Warrior of Light stormed Castrum Meridianium and destroyed the shield generators. Livia sas Junius confronted the party to prevent them from breaching the Praetorium, but was slain during the ensuing fight.
The airship Enterprise allowed to infiltrate the Praetorium with the Warrior of Light and their team to destroy the Ultima Weapon. As they descended through the immense fortress, the Magitek Reaper previously used to enter Castrum Centri was discovered inside the lower levels and blasted through concrete walls and past Ultima's Arms. Just outside the elevator lift that would take them to the Ultima Weapon. Nero tol Scaeva, Gaius' second in command and last remaining tribinus, confronted the group. Though defeated, he made his escape while exalted about Ultima Weapon's activation.
As the party descended the lift, Gaius appeared and was battled on the elevator. Though a fierce opponent, Gaius fared no better against the Warrior than his subordinates did. Gaius retreated into the Ultima Weapon's chamber and entered it's cockpit to pilot the massive weapon himself. Getting inside, the Warrior and their team battled the Weapon. Despite its immense power from having absorbed three primals, the light of the Mothercrystal gave the party an edge against the superweapon and gradually removed the primals.
As Gaius vexed in frustration, the Ascian Lahabrea appeared and explained that the shield of light could only be removed by bringing "the hammer of darkness." He activated the Heart of Sabik inside the Ultima Weapon, and released the spell Ultima. Though it destroyed much of the Praetorium, the party was shielded by Hydaelyn, who use the last of her strength to do so. Gaius attempted to defeat the adventurers once again, with Lahabrea attempting to unleash Ultima a second time, but more intervention from the Mothercrystal resulted instead of the Ultima Weapon's destruction.
Severely injured in the explosion, Gaius was knocked unconscious and discarded by Lahabrea, who then confronted the Warrior of Light himself, as the Scions were interfering with his plans to resurrect of "the one true god." Though he was initially victorious, the Mothercrystal once again brought the Warrior to victory, and a blade of light banished Lahabrea from Thancred's body. As the player escaped with an unconscious Thancred on the Magitek Reaper, Gaius accepted his defeat as the Praetorium was consumed in fire, though he survives its destruction and lives on as the Ascian-hunting mercenary Shadowhunter.
With the Ultima Weapon and Gaius van Baelsar defeated, the Eorzean Alliance celebrated on the shores of Lake Silvertear declaring the dawn of the Seventh Astral Era. But an an ear-splitting roar dampened the celebrations, reminding them that the Primal troubles are far from over.
Archon (Greek: ἄρχων, árchōn) is a Greek word for "ruler".
Ancient Athens was for a time ruled by three "archons", or magistrates, selected from the aristocracy.
Operation Archon was named for the Archons, as according to Alphinaud Leveilleur, "the Archons were twelve in one, and one in twelve...", and the Alliance consists of twelve separate factions during Operation Archon.