On the official Arkham origins twitter and instagram they said they will be revealing the next assassin in two days. They posted some pics as clues as to who it would be. One of them showed fire, and another was a police report on the assassin with everything blacked out except the crime, his height, and weight. Crime was theft, height 5'11", weight 165.
His height and weight matches firefly's on dc wiki and he is a thief. Also there was a pic with fire like I said before. Pretty much guaranteed its firefly. We will find out in two days, but c'mon, it's gonna be firefly.
So what do you think about firefly being in the game?