Celeste is the Bad Guy – Mirror’s Edge
In Mirror’s Edge, as she continues her fight against the bad guys in the bright yet empty world, Faith is confronted by a female assassin who possesses the same style, agility, and parkour abilities as her. Faith’s best friend, Celeste, also possesses those abilities and is supposedly the only other runner in the game’s world.
Later on in the game, once you know both of them, you find out that the assassin is actually Celeste. However, the lack of characters in the game signposts it early on. Since Celeste is the only runner you come across in the majority of the game, it isn’t a stretch to think that the assassin could be her. The initially un-named assassin moves in the same way and has the same physical attributes as Celeste so you may see the connection very early.