You’re a clone of the hero known as Nightwing, you’re the same age as him, and you were trained to fight like him, but without mercy, just like your ‘father’ Slade Wilson taught you. You and Rose were ordered to go on a mission and exterminate a traitor that used to work for Slade. And after a wild goose chase, the escape was foiled and the traitor was exterminated like Slade wanted. Suddenly the police sirens could be heard in the distance, so you two quickly fled to the shadows to avoid being detected by police, and you were both now watching the scene from a rooftop.

“Y’know I was hoping you wouldn’t chicken out. I thought you went soft after your little encounter with that Houdini-Girl.” Rose gently nudged you with her elbow, referring to Zatanna as the ‘Houdini-Girl’. And she must have seen you on a mission that was interrupted by Zatanna at some point