The Injustice Battle Arena may have wrapped up last week, but there'd be no ceasefire from the testers at NetherRealm Studios! Absent from the main contest: Catwoman & Harley Quinn feature in this bonus battle via DC Comics.

The pair of Gotham City Sirens appear in their Arkham City alternate outfits -- inspired by the hit game from fellow Warner Brothers developer, Rocksteady Games.

Arkham City versions of Catwoman, Joker & Batman featured in a store exclusive Injustice pre-order bonus [watch trailer]. Getting your hands on the Harley Quinn skin is as simple as completing the Girl Power Challenge in the game, or by collecting any Joker character card in the Free Injustice iOS App and synching with your WBID.

Relive the entire Injustice Battle Arena tournament via the arena archive. Sixteen heroes and villains fought their way through elimination brackets, leading fans to decide the ultimate battle between Batman versus Superman!

Injustice: Gods Among Us is now on sale at most good retailers for the PlayStation 3, Xbox 360 & Nintendo Wii U! The (In)Justice League invade Japan with localized versions in June [full story]. Discuss it all on the DC Universe Injustice forum!