GameStop's "Red Hood Story Pack" DLC introduces Batman series vigilante Red Hood as a playable character, and features a number of exclusive single-player missions. GameStop pre-order buyers will also receive the Harley Quinn Story Pack, which bundles an additional playable character and four challenge maps.
Today's DLC reveal follows up on GameStop's recent announcement that it would fund unique DLC for featured games. The Arkham series has a history of experimenting with retail- and platform-exclusive content; the PlayStation 3 version of Arkham Origins hosted exclusive Knightfall maps, and Arkham City's Catwoman DLC served as a retail-focused incentive to curb used game sales.
Batman: Arkham Knight will hit the PlayStation 4, Xbox One, and PC platforms in 2015.
Batman: Arkham Knight (June 2014)