The DC comics villain was revealed in a new trailer by GameSpot showing the mercenary using both his sword and firearms against the game's other heroes.
Deathstroke joins the growing list of heroes and villains from the DC Universe, including Batman, Harley Quinn, Superman, The Flash, Wonder Woman, Catwoman, Solomon Grundy, Nightwing, Cyborg, Green Arrow, Green Lantern and The Joker.
Announced in May, Injustice: Gods Among Us is said to have a deep original story, taking place in "a world where the lines between good and evil are blurred".
NetherRealm is developing the title following last year's success with Mortal Kombat. In 2008, the team also created Mortal Kombat vs DC Universe as Midway Games.
The developers have dropped the traditional three-round fighting system, opting instead for a "more cinematic" single-round system.
A Collector's Edition will be available, featuring steelbook casing, a character statue, two issues of a brand new DC comic book series and three character skins.
Injustice: Gods Among Us will be available on Xbox 360, PlayStation 3 and Wii U next April.
Watch the Injustice: Gods Among Us Green Arrow trailer below: