With the magitek field now out of commission, the path to the Ultima Weapon lies open. While the Immortal Flames sweep Castrum Meridianum and suppress the remnants of the enemy garrison, you and your comrades must fight your way to the innermost sector of the Praetorium, there to locate and destroy the Ultima Weapon. Cid's airship, the Enterprise, will bear you to the stage of the final confrontation.
— In-game description
- As of patch 6.1, extensive changes to general progression have been implemented, and certain cutscenes have returned to being skippable. As such, the rewards have been reduced. For the prior version, see The Praetorium/Old.
- Secure the command chamber: 0/1
- Make for the Laboratorium Primum: 0/1
- Power and board magitek armor: 0/1
- Defeat Nero tol Scaeva: 0/1
- Defeat Gaius van Baelsar: 0/1
- Ceruleum Vent: Unavoidable raidwide damage that must be healed through.
- Prototype Laser Alpha: Four circle AoEs will appear from the center and move toward the outside of the arena.
- Prototype Laser Beta: Circle AoEs will be placed on every player, requiring them to spread out.
- Grand Sword: A cone AoE targeting a random player.
There is an electrical field on the outside of the arena, giving people the debuff Electrocution that deals damage over time until they leave.
- Spine Shatter: Tankbuster.
- Iron Uprising: A frontal cone AoE that knocks players back.
- Activate: Summons a Magitek Death Claw that tethers to one player and slowly moves towards them, knocking player back when it gets to them. The players not tethered should kill it.
- Augmented Shatter: A stack on a random player, followed by Wheel of Suffering centered on the targeted player.
- Wheel of Suffering: A circle AoE that deals damage to all players near the boss. Players should stack together then move out of the following AoE.
- Augmented Uprising: Nero will hop to one side of the arena and attack a large potion of the arena with a cone AoE that should be avoided.
- Augmented Suffering: Nero will jump to the center and cast a knockback attack. Players should get into the center to avoid being flung into the electrical field.
- Innocence: Tankbuster.
- Horrida Bella: Unavoidable raidwide damage that must be healed through.
- Terminus Est: Gaius will fire several blue, flaming Xs. After a few seconds, a line AoE blast comes from the X dealing heavy damage to any players in its path.
- Phantasmata: Copies of Gaius will appear on the long side of the arena and each cast Terminus Est, marked by flaming Xs. Players should move out of the way of their path by moving in between two of them.
- Festina Lente: A stack marker on a random player.
- Ductus: Three circular AoEs appear on the short side of the arena and move along the length of the platform.
- Hand of the Empire: Each player will be marked by an unavoidable circle AoE. Players should spread out to avoid excess damage.
At 5% HP, Gaius will summon 4 Phantom Gaius adds that must be taken out while he charges up Blade Energy for his ultimate attack, Veni Vidi Vici, which will instantly kill the party if energy reaches 100%.
- Heirsbane: Each Phantom Gaius will target a random player, dealing moderate damage to them.
- Ductus: The party will continue to be bombarded with this and Phantasmata as they battle each Phantom Gaius.
- Horrida Bella: After Veni Vidi Vici is withstood, Gaius will spam a higher damage version of this until he is defeated.
This duty is associated with the following achievements:
|Mapping the Realm: Praetorium
|Discover every location within the Praetorium.
The Hour Of Reckoning
A fortress within a fortress rising at the heart of Castrum Meridianum, the Praetorium houses the XIVth Imperial Legion’s command center, wherefrom Gaius van Baelsar directed his army’s operations realm wide.
Occupying the underground levels is a magitek research facility headed by Tribunus Nero tol Scaeva, a brilliant engineer responsible for the development of myriad machina of war. Of the many projects to his name, none was more groundbreaking than the revival of the Ultima Weapon. Created to suppress eikons, it was the Black Wolf's key to his conquest of Eorzea—and the Alliance's primary target in Operation Archon.
The Ultima Weapon
A counter-primal weapon of unparalleled might, the Ultima Weapon is a relic of ancient Allag discovered deep beneath Gyr Abania in a nigh-forgotten, ruin-sized site. Through the ingenuity of Nero tol Scaeva, it was restored to working order and made battle-ready, but dark rumors surround its source of power, the Heart of Sabik, which some claim was gifted from the Ascians.
Gaius van Baelsar
A general and governor both, his many accomplishments include the conquest and political assimilation of five enemy cities. Fearsome in battle, he personally rose to challenge those adventurers who stormed Castrum Meridianum, wielding his gunblade Heirsbane with deadly effect.
The ancient magick sealed within the Ultima Weapon wreaked untold havoc, tearing open a crater of charred steel. Defeated, Gaius van Baelsar is said to have been consumed by ravenous flames.