Marvel Cosmic Invasion DLC: The Siege of Castle Doom Launches November 10

Update (October 2026): Dotemu has now dated the DLC. The Siege of Castle Doom launches November 10 on Steam, Nintendo Switch and Switch 2, PS4, PS5 and Xbox Series X|S. A trailer shown at New York Comic Con revealed its two new playable characters: Doctor Doom and the Invisible Woman (Susan Storm). Dotemu has not announced a price. The original August report follows.

Dotemu and Tribute Games have revealed the second paid DLC for their arcade brawler Marvel Cosmic Invasion. It’s called The Siege of Castle Doom, it’s built around a new game mode starring Doctor Doom, and it’s due out in fall 2026.

Announced Aug. 17, the expansion pairs that new mode with two new playable characters. Dotemu hasn’t said who they are or how the mode works — the reveal amounts to a name, a single piece of key art, and a short list of features. There’s no trailer, no gameplay, no exact date, and no price.

Is Doctor Doom playable?

Not confirmed. Doom is “central” to the mode, per Dotemu, but the studio hasn’t said he’s playable. Some outlets have run with that assumption; the announcement itself stops short of it. “Doom-themed” is accurate. “Doom playable” isn’t, at least not yet.

Two new characters, still a mystery

The two additions will push the roster from 17 to 19, and Doom’s presence has fans guessing at Fantastic Four names — Reed Richards, the Human Torch, and the Invisible Woman still aren’t in the game. Nothing’s confirmed, though, and Dotemu’s earlier roadmap pointedly referred to the game’s “Super Heroes (and Villains!),” which leaves room for the newcomers to be neither heroes nor members of the Four.

A second DLC, timed to Avengers: Doomsday

None of this is a surprise, exactly. Dotemu said back in May that Cosmic Invasion would get two paid DLC packs in 2026 and shipped the first, Cyclops & The Thing, that same month for $3.99. This week’s reveal just put a name and a theme to the second. Dotemu hasn’t priced Castle Doom, and there’s no word on whether it’ll be included with Game Pass.

The timing isn’t subtle. Marvel’s Avengers: Doomsday, with Doctor Doom front and center, is dated for Dec. 18, and a Doom expansion this fall lets the game ride that wave.

Built by the Shredder’s Revenge team

The base game has the résumé to earn the attention. Marvel Cosmic Invasion launched Dec. 1, 2025, from the Teenage Mutant Ninja Turtles: Shredder’s Revenge team, sits at 81 on OpenCritic, and landed a D.I.C.E. Awards nomination; Dotemu said it had passed 1.5 million players — players, not sales — by May. It’s a tag-team brawler running on a Cosmic Swap system that lets you field two fighters and flip between them mid-fight, with the launch campaign pitched against the cosmic villain Annihilus.

More on The Siege of Castle Doom — the date, the price, and those two mystery characters — is promised before it launches this fall.