Suicide Squad: Kill the Justice League is an upcoming game that is probably going to launch on February 2nd, after a few delays. It's made by Rocksteady, the Arkham Asylum series studio.

More playable characters are going to be added as free DLC. According to the publisher, anyway. Some people are predicting the game will not be a success.

The base game has Harley Quinn, Deadshot, Captain Boomerang, and King Shark.

Reskins, like a cosmetic item that turns King Shark into Killer Croc, will not count.

I am not a gamer. I am probably not going to play this game. I drew the topic for this market out of a hat. I asked if I could pick something else and the guy said no.

Edit:

"Post-launch, players can expect a continuously evolving Metropolis with free new playable villains, environments, weapons, in-game events, and more, all included with purchase of the base game."
This text from the store page may imply that Katana won't be one of the post-launch characters, since she's not a villain, but we'll see.