In a press release:

"Today, Warner Bros. Interactive Entertainment and DC Entertainment confirmed that Deathstroke will be a fully playable character in the challenge mode for Batman: Arkham Origins. Fans who pre-order the game for Xbox 360 video game and entertainment system from Microsoft, PlayStation 3 system or Windows PC will receive exclusive early access to the Deathstroke pack. "

The full 4:53 trailer can be seen below or in our video section.