The 2026/2027 roadmap for Warhammer 40,000: Space Marine 2 already looks promising, with multiple patches planned to introduce a variety of new content for players to enjoy. From fresh weapons and class reworks to seasonal cosmetics packs for fan-favorite Chapters of the Space Marines factions, players can also anticipate new modes, PvE Operations, and much more. One of the most exciting features coming to the game is actually in its next update (Patch 15), which gives fans access to a mode unlike anything the title has seen before.
Patch 15 is set to release on October 1, 2026, and already plans to introduce Heroic weapons and armor pieces for players to collect. At the same time, a rework to the Tactical class is being implemented, as well as Crucible changes and melee tool adjustments. However, these are not the alterations that are exciting players, as this Warhammer game is evolving in the patch to expand how fans can engage with every Easter Egg it has for the Space Marine humanity side of its vast universe.
The big addition to Space Marine 2 in Patch 15 is the introduction of Chaos Siege Mode, a new PvE game type for players to team up together in. This mode marks the first time players are able to take control of Chaos Space Marines outside of PvP, allowing them to embrace heresy in full force. Ordinarily, players were only able to embody “normal” Astartes soldiers, who serve humanity instead of the more malicious forces of Chaos. That being said, the Chaos Chapters of the Space Marines are some of the most popular in Warhammer, so of course they would be referenced in Space Marine 2 in some way.
Players could originally be a Chaos Space Marine in the Eternal War PvP matches, with one side being the Heretic Astartes and the other being typical Space Marines. Sides were picked at random, though, so you could never predict what side you were on. Chaos Siege Mode fixes this by ensuring you are a Chaos soldier from the very start, alongside all your allies. Mechanically, this simply changes the enemy Space Marines in PvE missions to normal ones instead of Chaos opponents, but this is still a big shift from what the game consistently presents.
This new perspective is exciting, beginning with a siege on Avarax with at least two sectors to play through. Developer Saber Interactive has promised that more sectors are planned for Chaos Siege Mode, which will likely give players more opportunities to fight Tyranids and Imperial Space Marines in different groups. As more Patch updates come, this mode has a chance to expand even further, adding new maps for Chaos troopers that are more varied. As far as we know, there are no gameplay differences between Chaos Space Marines and Imperial ones, with classes remaining the same, but missions and dialogue perhaps being changed.
The biggest problem with selecting Chaos Space Marines before was that players had no control of when they would be on the side of Chaos in PvP modes. This was always an issue in Space Marine 2, since the game gives you full customization over whatever Space Marine character you embody, including the Chaos ones. Most of the time, you could unlock dozens of cosmetics for a Chas Space Marine armor look, but never see it because PvP matchmaking never put you on the Chaos team. With Chaos Siege Mode, your aesthetic for Heretic Astartes are consistently selectable.
Each class isn’t faction specific in Chaos Siege Mode too, giving players greater flexibility for what Chapter they wish to represent. The PvP mode often sees players forced into Space Marine 2‘s Chapter assignment system when it comes to what class you choose, regardless of what side you’re on. For example, picking the Vanguard class on the Chaos side of PvP makes you from the World Eater Chaos Space Marine Chapter, the group who worships the blood god Khorne. Similarly, the Bulkwark class for Chaos is part of the Death Guard, the faction that is loyal to the other Chaos god Nurgle and his diseased legions.
Chaos Siege Mode opens the door for customized and personalized approaches to Chaos Space Marines for the first time. Fans have long wanted a chance to have the same level of expression for Chaos marines as they do Imperial ones, so this Patch almost removes the final barrier players had to create unique looks for every type of Space Marine out there. For Warhammer 40,000: Space Marine 2‘s third year of ongoing support happening in 2027, this is an excellent expansion of its available content.
