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Clear out junk files and repair common Windows errorsFree Scan →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →To complete the Astra Malorum main quest in Call of Duty: Black Ops 7 Zombies, build the LGM-1 by collecting four components and defeating O.S.C.A.R. with three map contraptions. Then solve the run-specific Cryo Chamber, brain, planetary-display, and Mars-pillar puzzles before defeating Caltheris. The steps below follow the walkthrough published by Call of Duty: Zombies Guides, updated July 7, 2026; PCGamesN and Dexerto also cover the quest’s broad sequence. Activision’s Season 01 announcement says the quest went live on December 4, 2025, while its Astra Malorum map page describes the setting but does not provide a full solution.
The walkthrough estimates a clear at one hour to one hour and forty minutes; that is the guide publisher’s estimate, not a measured average. Record the clues you find during your run: several codes and sequences are generated from in-game information rather than being universal.
Before you start: prepare for the quest
The detailed walkthrough lists Cryo Freeze and the LGM-1 as requirements. Its recommended boss setup is Juggernog with Turtle Shell and PHD Flopper with Environmentalist; treat these as recommendations, not mandatory choices. Choose a weapon and field upgrade that suit your play style, and collect equipment before starting the final fight.
Build the LGM-1
After turning on the power, collect four component types. The guide says these can be collected in any order.
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Collect the four components
- Car Battery: Shoot Ol’ Tessie’s hood with a Pack-a-Punched weapon to reveal the battery, then collect it.
- Aberrant Wiring: Shoot a flickering lamp post and collect the wiring.
- Damaged drone: Provoke O.S.C.A.R. until its drone shield appears, destroy one hovering drone, and collect the damaged drone.
- Three Absolute Zero Fragments: Equip Cryo Freeze and shoot three Aether Crystals. Collect the fragments they drop.
Kill O.S.C.A.R. with all three contraptions
Use each of the map’s three contraptions to kill O.S.C.A.R. once. The kills can be done in any order. Completing the third contraption kill yields the LGM-1.
- Luminarium: Trap O.S.C.A.R. inside and keep him there while the trap overcharges him.
- Museum Infinitum: Use the rocket trap with the three Absolute Zero Fragments.
- Observatory Dome: Shoot five leaking valves, then use the Harmonic Oculus to focus the viewfinder on the Sun. Lure O.S.C.A.R. into the resulting beam.
Get the Cryo Chamber Key
Wait for another O.S.C.A.R. and follow him without being detected. During the Thurston playback, he names three planets. Convert the planets to their positions from the Sun, keeping the same order in which they are spoken. Enter those three digits at the Observatory Dome terminal. A correct code lowers a platform containing the Cryo Chamber Key.
| Planet | Position from the Sun |
|---|---|
| Mercury | 1 |
| Venus | 2 |
| Earth | 3 |
| Mars | 4 |
| Jupiter | 5 |
| Saturn | 6 |
| Uranus | 7 |
| Neptune | 8 |
For example, if the playback names Mars, Venus, then Saturn, enter 4-2-6. Use the planets from your own playback rather than a fixed code.
Extract and protect the brain
- Take the Rock Saw from its display in the Museum Infinitum.
- Go to the cryo chamber in Machina Astralis and use the saw on the body to extract the brain.
- Carry the brain to the Luminarium and swap it with the brain in the container.
- Defend the Perfusion Machine during the lockdown.
- Carry the machine back to Machina Astralis and connect it to the device there.
Solve the Mars-coordinate and reading-list puzzles
Record Mars’s coordinates
Use the Harmonic Oculus telescope to line up Mars and write down the displayed DEC coordinates. If the display gives three digits, the walkthrough says to add a leading zero before entering the code at the machine on Machina Astralis’s second floor.
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Match the reading list to the Archive busts
Read Dr. Thurston’s Reading List on the Perfusion Machine screen. In the Archive of Orbis, each of the three busts corresponds to a shelf with three books. Match the names on the list to the books on each shelf, then turn that shelf’s bust once for every matching title. When the matches are correct, the attic opens. Take the Neptune model and place it in the planetary display in Machina Astralis.
Align the planetary display and open the route to Mars
Find the three papers around the map and use their planet and direction clues to align the planetary display. These are run-specific clues, so note what the papers say rather than relying on a presumed universal alignment.
Activate the brain device and defend the portal against O.S.C.A.R.’s drones. Continue through the resulting progression to reach Mars.
Complete the Mars steps
- Install the Perfusion Machine on the starting pedestal and wait for the cue.
- Shoot the distant pylons in this order: back right, back left, front right, front left. Then shoot the pylon above the teleporter.
- When the Ascendant Eye is drawn into the arena, collect it during the periodic anti-gravity and place it in the pedestal in the far-right corner.
- Use the LGM-1 to shoot the five exposed rods on the pillars.
- Return to the Harmonic Oculus and record the symbol sequence it shows. The static-noise symbol marks the one pillar symbol omitted from the code.
- Interact with the Mars pillars in the order indicated by the sequence.
Defeat Caltheris
Prepare before interacting with the Perfusion Machine to start the fight. Shock Mimics and Toxic Zombies appear during the encounter, according to the walkthrough. Keep moving, use the environment, and take the opportunity between attempts to prepare your equipment and field upgrade.
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Phase 1: Floating skull
Kill zombies to charge a pylon, then activate the Perfusion Machine to fire a beam at Caltheris. Repeat the charge-and-fire cycle three times to clear the phase. Avoid the tracking laser and aerial bombs.
Phase 2: Rock golem
Fire the LGM-1 to break the boss’s armor, then switch to a primary weapon and shoot the exposed blue weak point. Stay mobile to avoid thrown rocks and the close-range slam.
Phase 3: Caltheris Ascendant
Continue breaking armor with the LGM-1 and attacking the exposed weak point with your primary weapon. The attacks become more forceful, so maintain distance and make use of movement and cover.
Phase 4: Caltheris the Needle
The boss moves faster and leaves damaging aetheric pools. Avoid the pools, break the armor with the LGM-1, and use your primary weapon on the exposed weak point. The guide notes that an in-game power-up can provide reserve ammunition and infinite lethals during this phase.
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