When the first trailer for Batman: Arkham Knight came out in March, it ended on the note that those who pre-ordered the title would be entitled to play as Harley Quinn:
The trailer was also accompanied by a pre-order listing on the Gamestop website which indicated Quinn would be playable only in challenge maps:
A different story is perhaps being told from a tweet sent out yesterday from the official “Batman Arkham” twitter account (@BatmanArkahm,) that has a similar image updated to show that Harley Quinn will have her own story mission:
The “Arkham” series is no strangers to having guest characters in challenge maps: heroic characters like Nightwing and Robin, and even villains like Deathstroke and the Joker. If Harley Quinn does indeed have a story campaign of sorts, it will mark a series first of having a villain with a playable single player portion (I don’t count Catwoman, as she is more of a morally grey hero who ultimately helped Batman in the end in Batman: Arkham City.)
Of all the characters who could possibly have a story outside of the main game in Batman: Arkham Knight, Harley Quinn is easily the best choice given the ending of Batman: Arkham City and its subsequent add-on story. Each of the villains who are out for Batman’s blood have their own reasons, motivations and vendettas, but for Harley, it may be all that she has left to live for.