Looks like the game was unlocked. EDIT: Interesting, though yeah he was already part of the Knife of Dunwall and Brigmoor Witches episodes for the first game and Billie should offer some interesting perspective changes having only had a smaller role in the two DLC episodes until Dishonored 2 where the player could (optionally.) pick up on a bit more of her past. EDIT: Or it just shows up that way in Steam for some reason. EDIT: Ah it's out in Australia and a few other regions.