- “So begins the third phase of Operation: Archon, which entails a frontal assault upon Castrum Meridianum, Gaius van Baelsar's seat of power. Forming the main thrust, the Immortal Flames will strike at the stronghold with all their strength, though this is but a feint. While the garrison's eyes are drawn outwards, you and your comrades must steal past its defenses and attempt to deactivate the magitek field which protects the Praetorium, the fortress within a fortress wherein the Ultima Weapon is believed to be housed.”
- —Game Description
- Castrum Meridianum is unlocked through the main story quests.
- Full Party (8 Players) (2 Tanks, 2 Healers, and 4 DPS)
- Players must have completed the quest Rock the Castrum.
- Time Restriction: 120 minutes
- Rewards: 20 Allagan Tomestone of Poetics
- As of patch 4.2, to ensure new players are able to enjoy the cutscenes in Castrum Meridianum and the Praetorium, all cutscenes in these dungeons can no longer be skipped. Because this will increase the time required to complete these dungeons, completion rewards and Duty Roulette bonuses for these duties have been increased.
- Darken the searchlight: 0/2
- Darken the searchlight: 0/1
- Obtain incendiary #37: 0/2
- Destroy the ceruleum pump: 0/2
- Destroy the field generator: 0/3
- Imperial identification Key: 0/2
- Darken the searchlight: 0/1
- Darken the searchlight: 0/2
The Black Eft
One tank should tank The Black Eft while another tank should get the attention of the adds spawning at the doors. Players should avoid the heavy hitting Magitek Cannon ability.
- Photon Stream is an instant, frontal, ranged attack that does small to moderate amount of damage.
- Magitek Cannon is a large circular AoE attack that targets a random player. It will do heavy damage to all players hit.
- Imperial War Hound has a frontal column AoE ability that should be avoided.
- 8th Cohort Laquearius has a frontal cone AoE ability that should be avoided.
- Imperial Signifer is an add with spell casting abilities
Magitek Vanguard F-I
One tank should tank Magitek Vanguard F-I while the second tank grabs adds that spawn at the doors. Non-tank players should avoid the front of the boss.
- Cermet Drill is an instant, frontal melee attack that deals a moderate amount of damage.
- Drill Cannons is a frontal column, AoE attack that deals a heavy amount of damage to all players hit.
- Overcharge is a frontal cone AoE attack that deals heavy amount of damage and inflicts the debuff Paralysis to all players hit.
- 8th Cohort Signifer has a fire spell that should be avoided by moving out of the ground indicator.
- 8th Cohort Sagittarius has ranged attacks that apply DoTs to its targets.
- Magitek Reaper has a large circular AoE ability that deals heavy damage to all targets get. Move out of the ground indicator immediately.
Magitek Colossus Rubricatus
One tank should tank Magitek Colossus Rubricatus while the other tank tank the adds that spawn. Players should spread out to lessen the damage taken from Magitek Ray. Players should also avoid standing in front of the Magitek Vanguard H-1 adds.
- Grand Sword is an instant frontal cleave attack that deals a moderate amount of damage to all targets hit.
- Exhaust is a frontal column AoE attack that does a moderate amount of damage to all targets hit.
- Magitek Ray is an instant attack that randomly targets a player and deals a moderate amount of damage to the player and nearby players.
- Magitek Field gives Magitek Colossus Rubricatus the buff Vulnerability Down, reducing the damage it takes.
- 8th Cohort Laquearius has a frontal AoE cone attack that moderately damages all targets hit.
- 8th Cohort Medicus has the Cure spell that heals its ally.
- Magitek Vanguard H-1 has a frontal cone and column AoE attacks that deal heavy damage to all targets hit.
Livia sas Junius
- In this fight, players have to defeat Livia sas Junius in her Magitek Armor. In the boss room, there are Mark XLIII Artillery Cannons with Magitek Missle piles near them. When players click on these cannons, Magitek Loaders will load the cannons with missiles. Players can fire the cannons to do 3000 damage to Livia. One of the tanks should fire the cannons because the act draws the aggro of the boss. Tanks should tank Livia in the center of the room, away from the cannons, because Livia's cleave attacks could damage and destroy them.
- She will spawn adds throughout the fight. One of the tanks should take their aggro and prevent them from destroying the cannons.
- Photon Stream is an instant frontal attack that deals a small amount of damage
- Magitek Cannon is a large circular AoE attack that targets a random player. It deals heavy damage to all players caught in the AoE.
- Livia sas Junius is now on foot, stripped of her Magitek Armor. She possesses a different set of abilities with greater damage potentials. Players should dodge her Stunning Sweep, circular AoE attack, and Angry Salamander, frontal column AoE attack.
- At 3/4 and half HP, Livia will spawn a group of 7th Cohort Secutor Adds. They will target all target one player. That player should stay still so rest of the party members can AoE down the adds. At quarter HP, Livia will spawn a Magitek Colossus along with a group of 7th Cohort Secutors. One of the tanks should take the aggro of the Colossus while the rest of the group AoE down the Secutors and burst down the boss.
- Aglaia Bite is an instant melee attack that deals a moderate amount of damage.
- Delta Trance is an instant melee attack that hits a target 5 times rapidly.
- Roundhouse is an instant attack that deals a small amount of damage to all players nearby.
- Stunning Sweep is a circular AoE attack deals a moderate amount of damage and inflicts the debuff Paralysis to all players hit.
- Angry Salamander is a frontal column AoE attack that deals a moderate amount of damage to all targets hit.
- Aglaia Climb is a frontal attack that hits targets very rapidly.
- Order to Attack summons 7th Cohort Secutors.
- 7th Cohort Secutor is a melee damage dealer summoned by Livia in groups.
- Magitek Colossus has a frontal column AoE attack that deals moderate amount of damage to all targets caught. It also has an instant frontal cleave attack that should be avoided. Players should also spread out to lessen Magitek Ray damage.