Warhammer 40,000: Space Marine 2's Patch 15 is scheduled for release on October 1, 2026, focusing on the addition of the "Chaos Siege" PvE mode. For the first time, players will be able to team up and control Chaos Space Marines in the game's PvE content.
Previously, players could only play as the Chaos faction in "Eternal War" PvP matches, with the faction assigned randomly by matchmaking, offering no guarantee of using cosmetics prepared for Chaos characters. The new mode allows teams to start as the Chaos faction from the beginning, providing a more consistent showcase for these outfits.
"Chaos Siege" will begin with the Siege of Avarax, initially featuring at least two zones. Developer Saber Interactive plans to add more zones in the future. Compared to existing PvE content, the new mode will change the player's faction and opponents; while the current class system is expected to remain, it remains unclear whether and how much missions and dialogue will be adjusted.
Patch 15 also plans to add collectible Heroic-tier weapons and armor, along with adjustments to the Tactical class, arenas, and melee tools.