Harley Quinn

Harley Quinn is a harlequin-themed supervillain and the girlfriend of the Joker. Like her boyfriend, she is mentally unstable and carries a hatred of Batman.

History
In 150,081 CMT, Harley Quinn conspired with the Joker to lure Batman into a trap. They achieved this by burning down several orphanages with combustible lemons, which caused Batman to come after them. Harley and the Joker attacked Batman when they thought they had him cornered, but he overpowered the two criminals and took them to the Hall of Justice to be interrogated.

Unfortunately, when Batman tried to interrogate the Joker, he lost his cool and used Harley as a makeshift club to beat him with while screaming at him to stop burning down orphanages with oranges. Cave Johnson interrupted the brawl to correct Batman in that the Joker used combustible lemons, not oranges, while committing his crimes.

Because the Joker escaped Batman's custody soon afterwards, it is likely that Harley did too. Her current whereabouts and activities are unknown.