Doctor Doom is taking over the next expansion for Marvel Cosmic Invasion. Called The Siege of Castle Doom, the paid add-on brings a new game mode and two additional playable characters, with the villain positioned as the driving force behind the mode’s events. It follows the game’s first content drop and lines up with a wider Doom push across Marvel’s slate.
Quick answer: The Siege of Castle Doom is the second DLC for Marvel Cosmic Invasion, launching in fall 2026 on all platforms as a paid add-on with one new game mode and two new playable fighters, and Doctor Doom is central to it.
What The Siege of Castle Doom includes
The expansion is built around two confirmed additions and a single starring villain. Publisher Dotemu describes Doctor Doom as “central” to the mode’s events, which points to a Doom-focused scenario rather than a background cameo. The two new fighters have not been named yet.
| Detail | What is confirmed |
|---|---|
| Add-on name | The Siege of Castle Doom |
| Type | Paid DLC (second for the game) |
| Release window | Fall 2026 |
| Platforms | All platforms |
| New content | One new game mode, two new playable characters |
| Featured villain | Doctor Doom, described as central to the mode |
Note: Beyond these points, further specifics have not been revealed. The identities of the two new characters, the exact release date, and pricing are still unannounced.
How it builds on the base game and first DLC
Marvel Cosmic Invasion is a 2D tag-team beat-’em-up from developer Tribute Games and publisher Dotemu, released on December 1, 2025 for PlayStation 4, PlayStation 5, Nintendo Switch, Xbox Series S and X, and Steam. The campaign pits an all-star hero roster against Annihilus and his Annihilation Wave across more than a dozen locations, using a switchable two-character tag system for combos.
The Siege of Castle Doom is the second piece of DLC. The first expansion added Cyclops and The Thing as playable characters earlier this year, so this add-on continues the pattern of expanding the roster while introducing a fresh mode on top of the original content.
Why Doom is showing up now
The timing tracks with Doctor Doom’s larger moment across Marvel. He headlines Avengers: Doomsday, which reaches theaters on December 18, with Robert Downey Jr. in the role. Marvel has a habit of syncing its games to film releases, and it has already used titles like Marvel Rivals and Marvel Snap to promote Spider-Man: Brand New Day earlier in the year with themed skins and seasons.
Whether Doom himself becomes a playable fighter in the expansion has not been stated. What is confirmed is that he anchors the new mode’s story, making him the throughline of the add-on even if his exact playable status stays open.
Release window and platforms
The Siege of Castle Doom is scheduled for fall 2026 across all platforms the base game supports. No official day or time has been confirmed yet, so treat any single date as unannounced until Dotemu sets one. Because it is paid DLC, you will need the base game and a separate purchase to access the new mode and characters once it goes live.
You will know the expansion is available when it appears as a purchasable add-on on your platform’s store for Marvel Cosmic Invasion, with the new mode and two extra fighters selectable in-game after installation.
