User blog comment:Avataress0/Injustice/@comment-5060912-20130420235447/@comment-432124-20130421000622

Well, there were some cameos of Martian Manhunter, the Atom, and Giganta in the background during the game-play, so you would have to watch the walk-throughs to see them and you would have to look real hard for them. Plus, there was a scene of Green Arrow looking at a picture of Black Canary while sharpening one of his arrows, so that could count as a cameo.

And I also hope that they put in Black Canary, Martian Manhunter, and some others as DLC, though they wouldn't be part of the story mode.