Killer Croc
Who is he? Waylon Jones, a man born with atavism that gave him reptilian skin and sharp teeth. He usually works as hired muscle for crime lords in Gotham City, or he does his own thing and tries to eat Batman. Like, a lot of the time, he’ll try to eat someone, because he’s a freaking crocodile.
Why include him? Croc’s going to be making an appearance in the Suicide Squad movie due out in August, and DC’s definitely going to be capitalizing on that as much as possible. He’s been featured heavily in the promotion for both the film and the Suicide Squad comic for DC’s Rebirth initiative. The first Injustice played with the idea of characters of different size going up against each other, so why not continue that by having someone who, more often than not, can be as high as 11 feet tall?