X01 is an underground DMZ location introduced in Season 1 of Call of Duty: Modern Warfare 4. Hidden beneath the Hajin Exclusion Zone, this former GRANIT Arms black site has been taken over by enemy forces. Its underground network includes cargo bays, vehicle depots, laboratories, production lines, and a sealed Deep Vault.
Exploring X01 requires careful movement and resource management. Its multi-level layout, hostile patrols, and changing extraction conditions can make it difficult to complete objectives and leave safely. Ghost guides Operators through the new DMZ Orders, while stronger enemies create additional challenges deeper inside the facility.
This guide covers X01’s confirmed features, important enemy threats, the 3D Printer, Deep Vault exploration, and extraction tips.
Where to Find the X01 Underground Facility
X01 is located within the Hajin Exclusion Zone. Official Season 1 information identifies it as a former GRANIT Arms black site that has been seized by North Korean forces.
X01 was introduced as an underground location accessible through Hajin. The November 6 Season 1 update also describes it as a DMZ location within Hajin. Check the current deployment menu and in-game instructions for available entry options rather than assuming the original access method will remain unchanged.
The facility contains several major areas:
- Cargo Bays: Large storage areas connected to the underground military complex.
- Vehicle Depots: Sections associated with the facility’s military vehicle infrastructure.
- Underground Laboratories: Restricted areas tied to weapons development.
- Production Lines: Manufacturing sections from the original GRANIT Arms operation.
- Deep Vault: A sealed underground area and one of X01’s main exploration objectives.
These sections connect through tunnels, corridors, and multiple levels. Stay close to your squad when exploring unfamiliar routes, and check your surroundings before moving into another section.
Prepare Your Equipment for X01
X01 contains hostile forces and dangerous underground encounters, so bring a balanced loadout with enough ammunition, armor, and medical supplies for extended fights.
Night Vision Goggles are useful when navigating poorly lit sections. They can improve visibility in dark corridors and help you identify movement before entering unfamiliar areas.
The Sedative Inhaler is another useful item for avoiding surveillance. Its primary function is to hide Operators from UAVs and UAV Towers. The November 2 update increased its duration from 60 to 120 seconds. The November 6 Season 1 patch corrected its interaction with UAVs and UAV Towers upgraded through the UAV Upgrade trait.
However, the inhaler does not provide complete invisibility. Advanced UAV fire support can still detect Operators using it, so avoid relying on the item as your only form of protection.
X01 Enemy Threats: The Captain and Wheelson
The 100 Spirits NK faction operates around the facility, and stronger enemies make deeper exploration more dangerous. Pay attention to patrol positions and use cover when moving through narrow corridors.
The Captain
The Captain is a confirmed major threat associated with X01. Official Season 1 information identifies him as a Juggernaut accompanied by an elite guard.
The Threat Briefing: The Captain event requires Operators to enter X01, engage him, and collect sections of his Juggernaut helmet. These parts must be successfully extracted to count toward the event rewards.
Prepare enough ammunition and recovery supplies before approaching him. Keep your squad together during the fight, and check your objective progress before leaving the area.
The official briefing also confirms that the entire squad receives credit if one teammate successfully extracts with a scavenged Commander part.
Wheelson
Season 1 introduces an autonomous patrolling Wheelson as one of the DMZ Commanders listed on the Boss Board. However, the official announcement does not confirm that it always patrols inside X01 or that it is part of the Deep Vault route.
Check the Boss Board and current in-game intelligence before planning an encounter. Treat Wheelson as a separate commander threat unless your deployment information identifies its location.
Explore the Underground Labs and 3D Printer
X01’s cargo bays, vehicle depots, laboratories, and production lines reveal its original role as a GRANIT Arms weapons facility. Search accessible areas for useful equipment and intelligence, but avoid spending too much time in one location when extraction routes may become unavailable.
The November 6 Season 1 patch notes confirm that X01 contains an in-world 3D Printer. This is separate from the printer updates associated with the Forward Operating Base.
The pre-launch briefing did not provide a complete recipe list or detailed instructions for every X01 printer interaction. Check the current in-game prompts and requirements before using collected materials.
The FOB has its own printer and crafting system, with separate recipe and assembly updates in the Season 1 patch notes. Do not assume that recipes or requirements are identical between the two locations.
How to Approach the Deep Vault
The Deep Vault is one of X01’s main points of interest. Official Season 1 information confirms that Operators can descend through the underground facility and infiltrate this sealed area.
However, the pre-launch briefing did not provide a complete step-by-step access sequence. It also withheld details about some internal enemies, restricted areas, and equipment. Avoid relying on unverified room numbers, keycard combinations, or commander requirements as confirmed universal mechanics.
Before pushing deeper underground:
- Check your active DMZ Orders and identify the objectives related to X01.
- Bring enough ammunition, armor, and medical supplies for extended encounters.
- Stay together when moving through multi-level corridors.
- Follow Ghost’s updates as you access new areas and encounter threats.
- Check available extraction points before committing to a deeper route.
The Captain is explicitly associated with X01, making him an important target for the related Threat Briefing event. If your objective involves collecting his helmet sections, make sure your squad can complete the fight and extract with the required items.
Follow the current in-game instructions for any Deep Vault access requirements. The official briefing confirms the location but does not establish every detail of its internal access process.
Complete X01 DMZ Orders and Collect Rewards
Ghost serves as the Watcher for operations inside X01. He provides updates as Operators move deeper into the facility, tracks the route, and identifies emerging threats.
Pay attention to these instructions because DMZ Orders can direct your squad toward specific locations and objectives. The Captain’s Threat Briefing is one example: Operators must collect sections of his Juggernaut helmet and successfully extract with the recovered parts.
Not every DMZ Order necessarily follows the same completion rules. Some objectives may track actions completed during a deployment, while others require players to extract with specific items. Read each Order’s requirements instead of assuming all progress is saved in the same way.
Plan Your Extraction Before Exploring Deeper Areas
Extraction is a major part of surviving X01. The official Season 1 briefing warns that extraction points can close as Operators move deeper into the facility. Check the map and objective indicators throughout the deployment instead of waiting until your squad has collected valuable equipment.
Keep these points in mind:
- Check available extraction points before entering restricted sections.
- Save enough ammunition and medical supplies for the return journey.
- Stay together when moving through multi-level corridors.
- Review each Order’s extraction requirements before leaving.
- Move toward an available exit when the facility begins closing routes.
Improve Your Combat Preparation for X01
X01 combines underground exploration, armored enemies, and extraction pressure. Improving aim, recoil control, and target tracking can help your squad handle difficult encounters without wasting ammunition.
Players who want to practice weapon control and movement can use CoD MW4 Bot Lobbies to test their loadouts. Modern Warfare 4 Bot Lobbies also provide a controlled environment for improving target tracking before entering more demanding matches.
During X01 deployments, prioritize squad coordination, resource management, and objective completion. Keep track of available exits as you explore, and do not let valuable loot distract your team from a safe extraction.