Now that the Injustice: Gods Among Us demo is live on PSN and Xbox Live, the game’s associated Avatar goodies have also hit the Xbox Live Marketplace. Of the many offerings available (Wonder Woman/Superman/Batman logo shirts, etc), the costumes for Killer Frost and Ares seen above are by far the most interesting, since those characters haven’t been announced for the game.
Considering that every other available costume is for one of the game’s many playable characters, we feel safe in assuming these two villains are either unlockable fighters, or future DLC.