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Chaos Siege is a free PvE mode added in Space Marine 2’s Patch 15 on October 1, 2026. You play as Heretic Astartes fighting Tyranids and Loyalists. Focus Entertainment confirms availability on PlayStation 5, Xbox Series, and PC, but the official Patch 15 information does not specify Chaos Siege matchmaking, difficulty options, or reward thresholds. Focus Entertainment’s launch announcement and the Patch 15.0 notes establish what is confirmed.
What is Chaos Siege?
Chaos Siege is a PvE mode introduced in Patch 15. It puts players on the Heretic Astartes side against Tyranid forces and Loyalists. Cultists and a Helbrute support the Chaos side, and the Patch 15 notes identify the Hive map in the Avarax hive city. Read the Patch 15.0 notes.
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Focus Entertainment describes it as the first time players can use Chaos Space Marines in PvE in Space Marine 2. It is distinct from the game’s original Siege mode and from Crucible, another PvE feature added in Patch 15.
How do you access Chaos Siege?
Chaos Siege is part of the free Patch 15 update, which Focus Entertainment says is available for PlayStation 5, Xbox Series, and PC. You need the base game on a supported platform; the publisher announcement does not describe a separate paid Chaos Siege add-on. See the publisher’s launch announcement.
#1 Best Overall
- Embody the superhuman skill and brutality of a Space Marine. Unleash deadly abilities and devastating weaponry to obliterate the relentless Tyranid swarms. Defend the Imperium in spectacular third-person action in solo or co-op modes.
- Purge the relentless Tyranid swarms as legendary Space Marine Titus in a spectacular new campaign. Play solo or with up to 2 friends in 3 player co-op.
- Enjoy intense, gory and fast-paced third-person action with hundreds of enemies on screen, from the creators of blockbuster co-op shooter World War Z.
- Standard edition includes: Base game, Macragge’s Chosen DLC, with 3 unique cosmetics for your Bolt Rifle, Chainsword & Power Armour
The official material cited here does not give an exact in-game menu path. If you cannot find the mode, first confirm that the game has updated to Patch 15, then check the current in-game mode menus. Do not rely on an unverified navigation path.
How many Chaos Siege sectors are available?
The official Steam announcement says Chaos Siege has two sectors available, with a third in development. This is the status reported in the announcement; sector availability can change as the game receives updates. Check the official Steam announcements for later changes.
Rank #2
- Purge the relentless Tyranid swarms as legendary Space Marine Titus in a spectacular new campaign. Play solo or with up to 2 friends in 3 player co-op.
- Enjoy intense, gory and fast-paced third-person action with hundreds of enemies on screen, from the creators of blockbuster co-op shooter World War Z.
- Defend the Imperium as your own Space Marine in an endlessly brutal and replayable PvE missions up to 3 players featuring 6 classes, unlocking new skills and cosmetics.
- Wage eternal war on your enemies in ferocious 6v6 PvP matches and bring glory to your faction!
- The Ultima Limited Edition contains: Warhammer 40,000: Space Marine 2, SteelBook case with exclusive artwork, Season Pass 1, Season Pass 2, Macragge's Chosen DLC
How does Chaos Siege matchmaking work?
The Patch 15.0 notes do not specify Chaos Siege squad size, public queue rules, crossplay behavior, or whether private lobbies are supported. Those details are not established by the official information cited here.
Do not apply Crucible’s matchmaking rules to Chaos Siege. Patch 15 describes Crucible as using separate matchmaking from standard PvE, but that statement concerns Crucible, not Chaos Siege. The Patch 15.0 notes cover both modes.
Rank #3
- Brand new. UK Import PAL version. Game in English. UK PSN account may be required for any online features.
What difficulty should you choose?
The official Patch 15 information cited here does not list Chaos Siege difficulty choices or explain how they affect enemy pressure, survivability, or rewards. It therefore does not support a recommendation for a particular setting. Check the in-game options for the choices currently available to you.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What rewards does Chaos Siege give?
The Patch 15.0 notes cited here do not establish Chaos Siege-specific reward amounts, unlock conditions, or thresholds. In particular, Crucible XP and Lamenters armor progression belong to Crucible; do not assume those rewards apply to Chaos Siege.
Rank #4
- Includes 2 multipart plastic Space Marines Intercessor miniatures with distinct poses. Also includes a Starter paint brush
- Paints include – - 1 Abaddon Black (Base) – 1 Macragge Blue (Base) – 1 Mournfang Brown (Base) – 1 Leadbelcher (Base) – 1 Retributor Armour (Base) – 1 Corax White (Base)
- These miniatures are unpainted and need to be assembled. We recommend using Citadel Plastic Glue and Citadel Paints.
For current mode-specific reward details, consult the game’s in-mode reward information or later official announcements. The two modes’ rules and rewards should be treated separately unless the developers explicitly connect them.
Quick Recap
What is confirmed—and what remains open
- Confirmed: Chaos Siege is a Patch 15 PvE mode featuring Heretic Astartes against Tyranids and Loyalists, with Cultist and Helbrute support, on the Hive map in Avarax.
- Confirmed: The publisher describes Patch 15 as a free update available on PS5, Xbox Series, and PC.
- Confirmed as reported in the Steam announcement: Two sectors are available and a third is in development; later announcements may change that count.
- Not specified in the official Patch 15 material cited here: Chaos Siege player count and matchmaking details, difficulty choices, and reward thresholds.
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