Marvel Tōkon: Fighting Souls Open Beta Fails to Run on Steam Deck Due to Anti Cheat Error

The open beta for Marvel Tōkon: Fighting Souls is currently unavailable on Steam Deck because its anti cheat system does not support the handheld’s Linux based operating environment.

The beta displays a network error shortly after launch, stating that no compatible anti cheat module can be found for the game and platform. The message then forces the application to close before players can reach a match or test its performance.

Changing Proton versions does not appear to solve the problem. Attempts to install Easy Anti Cheat manually have also failed, suggesting that the required Linux support must be enabled by the game’s developer rather than fixed through a simple adjustment on the Steam Deck.

The issue currently applies to the open beta. It does not confirm that the finished game will remain incompatible with SteamOS, but it creates uncertainty ahead of the full release.

The anti cheat system blocks access before gameplay begins

Marvel Tōkon: Fighting Souls uses an online anti cheat system to prevent unfair modifications and protect multiplayer matches. On Steam Deck, the game appears unable to load the module required for that protection.

This prevents the beta from connecting properly, even though the remaining game files may otherwise be capable of running through Proton.

Proton allows many Windows games to operate on Linux by translating Windows software instructions into formats supported by SteamOS. However, anti cheat compatibility depends on additional support from the developer and the company providing the security technology.

Easy Anti Cheat can work with Proton, but that support is not always enabled automatically. Developers may need to activate the correct Linux components, include them in the game package and ensure that the online services accept SteamOS connections.

Players cannot reliably add this support themselves. Manual installation may place anti cheat files on the system, but the game’s servers and configuration must also recognise the platform.

The beta problem may not affect the finished game

The current error could be limited to the open beta build. Test versions are often prepared separately from final releases and may not include every platform related component.

Arc System Works and the publishing team still have time to update the anti cheat configuration before launch. Steam Deck compatibility may also improve through a later beta patch or release day update.

However, there is no confirmation that SteamOS support will be added. Until the developer provides a clear response, Steam Deck owners should not assume the game will work at launch.

The concern is significant because fighting games can be well suited to portable systems. Short matches, training modes and local practice make them convenient for handheld play, while the Steam Deck’s controls can support most standard fighting game inputs.

Online competitive play still requires reliable anti cheat support. Without it, the game may remain restricted to Windows based handhelds and desktop computers.

Windows handhelds should still be able to access the beta

The problem is linked to Linux and SteamOS rather than the Steam Deck’s hardware performance. A handheld running Windows may be able to launch the beta normally because it can use the anti cheat module designed for Microsoft’s operating system.

That includes devices where players have installed Windows manually, although replacing SteamOS introduces additional driver, interface and maintenance considerations.

For most Steam Deck owners, the practical choice is to wait for an official compatibility update. Repeatedly changing Proton versions or modifying anti cheat files is unlikely to help when the required support has not been enabled by the developer.

Marvel Tōkon: Fighting Souls remains scheduled for release on August 6. The open beta’s failure on Steam Deck is disappointing, but it is too early to treat it as proof that the finished game will never support Valve’s handheld.