Updated October 7, 2026
Chaos Siege in Space Marine 2 isn't simply a series of increasingly difficult enemy waves. The mode can mix Tyranid attacks, Imperial forces, objective-based tasks and major Terminus encounters.
A run can therefore change pace several times. You may need to restore a generator, capture Vox Systems, defend a beacon, escort Servo-Skulls or override an Imperial signal before dealing with another major threat.
The progression below follows a Chaos Siege run through Wave 20. It provides a practical reference for the objectives, enemy threats and major Terminus encounters shown during that run.
Important: The exact progression documented here should not be treated as a guaranteed script for every Chaos Siege session. The boss and objective examples below describe this run and are intended as a progression reference.
Quick Answer
Chaos Siege in Space Marine 2 isn't simply a series of increasingly difficult enemy waves. The mode can mix Tyranid attacks, Imperial forces, objective-based tasks and major Terminus encounters.
A run can therefore change pace several times. You may need to restore a generator, capture Vox Systems, defend a beacon, escort Servo-Skulls or override an Imperial signal before dealing with another major threat.
The progression below follows a Chaos Siege run through Wave 20. It provides a practical reference for the objectives, enemy threats and major Terminus encounters shown during that run.
Important: The exact progression documented here should not be treated as a guaranteed script for every Chaos Siege session. The boss and objective examples below describe this run and are intended as a progression reference.
📋 Table of Contents
- How Chaos Siege Waves Work
- Waves 1–5: The First Terminus Encounter
- Waves 6–10: Objectives and Multiple Bosses
- Waves 11–15: Escalation and the Hive Tyrant
- Waves 16–20: Late-Run Objectives
- How to Manage Requisition Between Waves
- What Are Terminus Waves?
- Does Wave 20 Always End Chaos Siege?
- FAQ
- Final Tips for Surviving Chaos Siege
How Chaos Siege Waves Work
Chaos Siege puts you on the Chaos side, with Heretic Astartes fighting Tyranid forces and Loyalists.
That means the threat isn't always the same from one wave to the next. Some waves focus primarily on eliminating enemies, while others add an objective that forces your squad to move around the map, capture an area or defend a specific location.
There are also major Terminus Waves, which introduce powerful threats.
The most useful way to approach each wave is to think about three things:
- What enemy threat is coming?
- What objective do we have to complete?
- What resources will we need for the next difficult encounter?
That becomes increasingly important as the waves progress and enemies become stronger.
Waves 1–5: The First Terminus Encounter
Wave 1 — Tyranids and Your Starting Resources
The run begins with a preparation period before Wave 1.
Tyranids are identified as the incoming threat, giving the squad time to prepare before the fighting begins.
In this run, the starting Requisition pool is 600.
Don't assume that number is a universal starting amount for every Chaos Siege session. Instead, it shows why the opening preparation period can be useful.
Tip: Don't spend Requisition simply because the terminal is available. Consider whether the purchase will actually help with the immediate encounter or a more difficult wave ahead.
Wave 2 — Restore the Generator
Wave 2 introduces one of the first objective-focused encounters:
Restore the Generator (1/2)
Instead of simply clearing enemies, the squad has to interact with industrial machinery and restore the sector's power.
Once the generator objective is completed, the Chaos Lord confirms that the power grid is operational.
This is an early example of why Chaos Siege isn't a pure kill-count mode. When an objective appears, completing it is the priority.
Wave 3 — Extremis Pressure
Wave 3 returns to an incoming-threat objective, but the encounter includes an Extremis-level priority target.
This adds another layer of pressure beyond simply dealing with Minoris enemies.
When an Extremis target appears, keep the squad coordinated and avoid allowing the priority enemy to disrupt your progress.
Wave 4 — Imperial Forces and Escalating Threat
Wave 4 switches the objective to:
Eliminate the Imperial Forces
The wave also displays the:
ESCALATING THREAT: ENEMIES HAVE BECOME STRONGER
warning.
This is a useful point to start paying closer attention to your remaining resources.
If the current wave is manageable, there is little reason to spend Requisition simply for the sake of spending it. Keeping resources available for a major encounter can give the squad more options.
Wave 5 — Carnifex Terminus Wave
Wave 5 is the first major Terminus milestone shown in this run.
The game announces:
TERMINUS WAVE STARTED
A Carnifex appears as the Terminus threat, with the objective:
Eliminate the Terminus Threat
This is a significant difficulty spike compared with a standard incoming-threat wave.
Use the preparation period before the fight to make sure the squad has enough ammunition and support for the encounter.
Don't assume Wave 5 is the end of the sector. The run continues after the Carnifex is defeated.
Waves 6–10: Objectives and Multiple Bosses
Wave 6 — Tyranid Threat
After the first Terminus encounter, the run returns to a Tyranid-focused wave.
Use the preparation period to check ammunition, reposition your squad and decide whether another Requisition purchase is actually necessary.
The important point is not to treat every post-boss wave as another Terminus encounter.
Wave 7 — Capture the Vox Systems
Wave 7 introduces a more complicated objective:
Capture Vox System Alpha
Capture Vox System Beta
The capture zones require the squad to stay focused on the objective while dealing with incoming enemies.
This is different from a normal elimination wave because killing enemies alone isn't enough. Your team needs to maintain control of the required zones.
If you're having trouble with objective-based Chaos Siege encounters, see our Space Marine 2 Chaos Siege Objectives: How Beacon, Altar and Imperial Tasks Work.
Wave 8 — Defend the Beacon
Wave 8 changes the objective again:
Defend the Beacon
The squad has to protect the beacon while Tyranids pressure the area.
The wave also displays another:
ESCALATING THREAT: ENEMIES HAVE BECOME STRONGER
warning.
The important thing here is to avoid allowing the fight to pull the entire squad too far away from the objective.
If the game is asking you to defend something, maintaining control of the objective is more important than chasing an enemy across the map.
Wave 9 — Eliminate the Imperial Forces
Wave 9 switches back to an Imperial-force objective:
Eliminate the Imperial Forces
The objective reaches completion once the remaining Imperial forces have been eliminated.
Rather than spreading the fight across the entire arena, keep the squad focused on finishing the objective efficiently.
Wave 10 — Carnifex and Neurothrope
Wave 10 begins another:
TERMINUS WAVE STARTED
This time, the run shows both a Carnifex and a Neurothrope as major threats.
That makes this one of the more demanding encounters in the documented progression.
When multiple major threats are active, avoid splitting the squad unnecessarily. Concentrate fire when possible and make sure everyone understands which target needs attention.
Wave 10 is also a good example of why keeping some Requisition available can be more useful than spending everything during easier waves.
Waves 11–15: Escalation and the Hive Tyrant
Wave 11 — Rebuild After the Boss Fight
Wave 11 returns to an incoming-threat encounter.
After the Wave 10 fight, use the preparation period to check your resources before moving into the next objectives.
Pay attention to:
- Ammunition
- Armour
- Available support
- Requisition
- Squad health
- Positioning
The key is to avoid entering the next difficult objective with resources already depleted.
Wave 12 — Escort the Servo-Skulls
Wave 12 introduces:
Escort Servo-Skulls
The objective progresses through three stages:
1/3 → 2/3 → 3/3
This is another example of why Chaos Siege cannot be approached as a simple survival mode.
The squad has to keep the objective moving while enemies continue attacking.
If your team spends too much time chasing enemies away from the escort route, the objective itself can become the main source of lost time.
Wave 13 — Incoming Threat
Wave 13 returns to:
Eliminate the incoming threat
The wave provides another opportunity to prepare for the increasingly difficult encounters later in the run.
Check your ammunition and Requisition before moving forward rather than waiting until a major Terminus encounter has already started.
Wave 14 — Escalating Threat
Wave 14 returns to:
Eliminate the Imperial Forces
and again displays:
ESCALATING THREAT: ENEMIES HAVE BECOME STRONGER
This makes resource management increasingly important.
If your team has enough firepower to handle the current wave, you don't necessarily need to purchase every available support option.
Keep some flexibility for the next major encounter.
Wave 15 — Hive Tyrant Terminus Wave
Wave 15 is another major milestone in the documented run.
The game announces:
TERMINUS WAVE STARTED
and the objective becomes:
Eliminate the Terminus Threat
The boss is a Hive Tyrant.
This is one of the most dangerous encounters in the run because the Hive Tyrant can dominate the arena while the squad is also dealing with surrounding enemies.
How to prepare for the Wave 15 Hive Tyrant
Before starting the encounter:
- Make sure the squad is properly resupplied.
- Avoid unnecessary Requisition purchases.
- Have a plan for dealing with surrounding enemies.
- Use available defensive or support options when they are useful.
- Keep access to ammunition in mind before committing to the fight.
A Helbrute can also provide additional Chaos support during difficult encounters. For a dedicated explanation of its deployment and role, see our Space Marine 2 Chaos Siege Helbrute: How to Deploy and Use It.
Don't stop preparing after Wave 15
The Hive Tyrant is not the end of the documented run.
Waves 16–20 introduce additional objectives and another major Terminus encounter.
Waves 16–20: Late-Run Objectives
Wave 16 — Tyranids Return
Wave 16 returns to a Tyranid-focused threat.
After the Wave 15 Hive Tyrant encounter, use the preparation period to restore ammunition and decide which support options are actually worth buying.
Don't assume you need to spend heavily just because you have survived a Terminus wave.
Wave 17 — Override the Imperial Signal
Wave 17 introduces a particularly unusual objective:
Override the Imperial Signal
The Chaos Lord directs the squad to interface with Imperial cogitators and seed the defense network with false information.
The objective requires interacting with the terminal while dealing with the surrounding threat.
Once completed, the false signal is activated and the enemy response is misdirected.
This is a good example of how later Chaos Siege objectives can change the way your squad has to move around the map.
Wave 18 — Neurothrope and Beacon Defense
Wave 18 combines two major problems.
The squad has to:
Eliminate the Terminus Threat
Defend the Beacon
The Terminus threat is a Neurothrope, which also creates visibility problems through its psychic effects.
This makes Wave 18 particularly demanding because the squad cannot simply abandon the Beacon to chase the boss.
How to handle Wave 18
Keep at least part of the squad focused on the Beacon while dealing with the Neurothrope.
Avoid allowing the fight to pull the entire team too far away from the objective.
The priority isn't simply:
Kill the Neurothrope.
It is:
Kill the Neurothrope without losing control of the Beacon.
That distinction makes this encounter more demanding than a straightforward Terminus fight.
Wave 19 — Eliminate the Imperial Forces
Wave 19 switches back to:
Eliminate the Imperial Forces
This is another objective-focused encounter before the next major Terminus milestone.
If your Requisition reserves are low, be especially careful about unnecessary purchases.
Wave 20 — Hive Tyrant Terminus Wave
Wave 20 begins with:
TERMINUS WAVE STARTED
and:
Eliminate the Terminus Threat
The Terminus threat in this run is another Hive Tyrant.
After defeating it, the run reaches the Wave 20 completion state and displays a request to return to the Battle Barge.
The screen also indicates that the Siege continues.
That is important because this run documents what happens after the Wave 20 encounter, but it does not establish that Wave 20 is the universal endpoint for every Chaos Siege session.
How to Manage Requisition Between Waves
Requisition is one of the most important resources in Chaos Siege because support purchases can make difficult encounters considerably easier.
However, spending everything as soon as you can isn't necessarily the best approach.
1. Save for difficult encounters
Terminus waves are obvious points where additional support can be valuable.
If the current wave is manageable, consider keeping some Requisition for the next major threat.
2. Match purchases to the objective
Different objectives can create different support needs.
A Beacon defense, for example, can require a different approach from a straightforward enemy-clear wave.
Think about what the squad actually needs instead of automatically buying the most expensive option.
3. Use preparation periods
Between waves, take a moment to:
- Check your ammunition.
- Resupply if necessary.
- Look at your Requisition balance.
- Decide whether support is needed.
- Prepare for the next objective.
A short preparation check can prevent you from entering a difficult encounter without the resources you need.
4. Consider the Helbrute for major pressure points
The Helbrute can provide heavy Chaos support during difficult encounters.
It can be particularly useful when the squad needs additional pressure against tougher enemies, but there is no reason to deploy it simply because the option is available.
For the full deployment explanation, see our Chaos Siege Helbrute guide.
5. Keep resources available after Wave 15
The Wave 15 Hive Tyrant isn't the end of the documented progression.
Waves 17 and 18 introduce demanding objectives, while Wave 20 brings another Terminus encounter in this run.
Keeping some resource flexibility for the later waves can therefore be more useful than spending everything to make an easier wave slightly faster.
What Are Terminus Waves?
Terminus Waves are major Siege encounters built around powerful threats.
The documented run shows the following major Terminus encounters:
| Wave | Terminus threat in this run |
|---|---|
| 5 | Carnifex |
| 10 | Carnifex + Neurothrope |
| 15 | Hive Tyrant |
| 20 | Hive Tyrant |
The important point is that these are the Terminus encounters shown in this particular run.
The table should not be treated as a guaranteed boss lineup for every Chaos Siege session. Instead, use it as a practical reference for the progression documented here and prepare for major encounters at the relevant Terminus milestones.
Does Wave 20 Always End Chaos Siege?
Not necessarily.
In the run documented here, defeating the Wave 20 Hive Tyrant leads to a completion state and a request to return to the Battle Barge.
The screen also states that the Siege continues.
That makes Wave 20 an important late-run milestone, but this run alone does not establish that every Chaos Siege session must end at Wave 20.
If you're trying to survive longer, don't spend everything simply because you've reached Wave 15. The waves that follow can still introduce difficult objectives and another major Terminus encounter.
Does Chaos Siege Have Different Objectives From Normal Waves?
Yes.
The documented run includes objectives such as:
- Restore the Generator
- Capture Vox Systems
- Defend the Beacon
- Eliminate Imperial Forces
- Escort Servo-Skulls
- Override the Imperial Signal
- Eliminate the Terminus Threat
For a deeper breakdown of the major objective types, see Space Marine 2 Chaos Siege Objectives: How Beacon, Altar and Imperial Tasks Work.
FAQ
What happens on Wave 5 in Space Marine 2 Chaos Siege?
Wave 5 is a Terminus milestone. In the run documented here, a Carnifex appears as the Terminus threat.
What happens on Wave 10 in Chaos Siege?
Wave 10 is another Terminus encounter. The documented run features both a Carnifex and a Neurothrope.
Is the Hive Tyrant always on Wave 15?
Don't assume that the Hive Tyrant shown at Wave 15 in this run is a guaranteed boss assignment for every Chaos Siege session.
What objectives appear in Chaos Siege?
The documented run includes objectives such as restoring a generator, capturing Vox Systems, defending a beacon, eliminating Imperial forces, escorting Servo-Skulls and overriding an Imperial signal.
What is a Terminus Wave in Space Marine 2?
A Terminus Wave is a major Siege encounter featuring a powerful Terminus-level threat.
Should I save Requisition for later waves?
Yes. Avoid spending Requisition simply because you can. Keeping some resources available for Terminus encounters and difficult objective waves gives your squad more options.
Does Chaos Siege end at Wave 20?
Not necessarily. In the documented run, Wave 20 ends with a Hive Tyrant defeated and a request to return to the Battle Barge, while the Siege is indicated to continue. That should not be treated as a universal rule that every Chaos Siege session ends at Wave 20.
Can the Helbrute help against Terminus enemies?
Yes. The Helbrute is a Chaos support option that can provide additional heavy combat power during difficult encounters. See our Space Marine 2 Chaos Siege Helbrute guide for more details.
Final Tips for Surviving Chaos Siege
The biggest lesson from the Wave 1–20 progression is that Chaos Siege isn't about surviving one difficult boss and assuming the hard part is over.
Instead:
- Use early waves to build resources.
- Pay attention to the objective, not just enemy kills.
- Prepare for major Terminus encounters at the relevant wave milestones.
- Start preparing before Wave 15 rather than during the Hive Tyrant fight.
- Don't spend all your Requisition immediately after surviving a difficult wave.
- Keep the squad coordinated during major boss encounters.
- Treat Beacon, escort and signal objectives differently from normal combat waves.
- Remember that surviving Wave 15 still leaves important late-run encounters ahead.
- Use the Wave 1–20 progression as a reference, not a guaranteed script for every run.
If you're also working toward the Chaos Relic Armour, remember that Chaos Siege itself isn't the separate unlock route for that armour. Our guide Space Marine 2 Chaos Siege: Can You Unlock Chaos Relic Armour? explains how that progression works.
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