She was a henchmen of the Joker. The Batman chased her down to find Joker's location, as she had kidnapped Judge Dent's children. He chased her to the ledge of the building around Crime Alley. Batman dropped her off the roof, but she was luckily saved by you, who was luckily standing under the roof top her and Batman were fighting on.

Yo-Yo’s physical description, she wears a deep scarlet coloured bodysuit with one whole sleeve and the other sleeve missing, and has blonde hair too.