Lobo. The Injustice: Gods Among Us DLC announcement was made by NetherRealm Studios creative director/Mortal Kombat mogul Ed Boon, during NetherRealm's extended wrap-up of its Battle Arena superhero popularity contest. No information was revealed regarding when Lobo will be available, though we can surmise from previous information that he'll probably cost about five dollars.
Described as "a brawler, but a really fast brawler," Lobo is a ranged character that fights with his chains, according to Boon. After each fight, Lobo will return to his day job as an extra on the set of mid-90s television series Renegade.
... Okay, that last bit might be made up.