- Has approximately 100,000 HP
- Immune to Stun but susceptible to other debuffs including Slow and Elegy.
- Uses draw-in on current hate target at certain intervals if too far out of range.
- Uses the following TP moves:
- Antimatter: Single-target Light magic damage. Ignores Utsusemi.
- Energy Screen: Temporary physical damage immunity (cannot be up at the same time as Mana Screen).
- Mana Screen: Temporary magical damage immunity (cannot be up at the same time as Energy Screen).
- Catastrophic Malfunction: AoE damage and reduces elemental resistances.
- >50% HP: Followed with a tier V nuke or Comet.
- <50% HP: Followed with a -ja nuke, Banishga IV, or Meteor.
- Armor Buster: Physical AoE damage and gravity. Can be absorbed by shadows.
- Chemical Bomb: Conical AoE physical damage, Slow, and Elegy.
- Equalizer: Physical AoE damage and knockback.
- Wire Cutter: High single target physical damage attack. Can be absorbed by shadows/third eye.
- Hydro Cannon: Conical water damage and poison.
- Turbofan: Conical wind damage and silence.
- Smoke Discharge: Conical earth damage and petrification.
- Flame Thrower: Conical fire damage and plague.
- Cryojet: Conical ice damage and paralysis.
- High-Tension Discharge: Conical thunder damage and stun.
- Dissipation: High AoE damage, terror (up to 10 seconds), full dispel (except reraise, food effects, and Embrava)
- At 49%, 39%, 29%, 19%, 9% HP: Citadel Siege: Single target instant KO.
- Citadel Siege can be avoided if the target is at sufficient distance from Arch-Ultima (start running at 50%, then drop him to 49%, etc.; maintain some proximity to avoid being drawn in). Citadel Siege will be skipped if Arch-Ultima is in the process of readying Citadel Buster.
- <50% HP Citadel Buster: 30' AoE severe light elemental damage
- Citadel Buster is preceded by a warning countdown starting at 30 seconds ("30...") and continuing to warn players at various intervals. Current hate target will continue to be drawn in during this time, but other actions will cease.