The post is part of a pre-order offer, but does not give details on the extent of Deathstroke's playability. In Batman: Arkham City, players were able to take on the role of Catwoman through downloadable content.
Batman: Arkham Origins was announced in April for Xbox 360, PlayStation 3, Windows PC and Wii U. The game takes place before series predecessors Arkham City and Arkham Asylum, where Batman is still young and "unrefined." Early reports suggest that the game will have multiplayer options.
Batman: Arkham Origins is currently scheduled for release Oct. 25.