There. The slightest tensing of his muscles. Most would have missed it, especially in the low light, but not Batgirl. She smiled behind her mask and stepped closer.
He spoke roundhouse kick to her. Very eloquent. He had a kung fu accent, and a familiar one. His teacher was good.
She sidestepped and caught his leg in a fluid motion, using the momentum to toss him to the rooftop. Her hand placement could have easily allowed her to strike a nerve cluster in his leg with her knuckles, but that would be a poor gauge of his skill.
Wanting to narrow down which disciple he had, she adopted a stance she'd been taught by her father David Cain: one that had been taught to him by the League of Assassins.