Nightwing was just about to start heading back from his nightly patrol before spotting you, seated atop a rooftop, swinging your legs off the building, staring down at the ground below, watching people walk along, some chatting.

You appeared to be wearing a belt with different weapons holstered in it. Which immediately indicated for him that you had something to do with being a vigilante.. or maybe a villain, so he decided to approach you to talk, and figure out whether you were good or bad.