The first time she sees him kill, he doesn't know she's looking.
They had both outgrown their mantles, long outgrew them, and while Irey tried her hardest to stay in the skirted Impulse costume she'd grown up in, Damian couldn't take his father's quick enough. He had grown into it, worked hard for it, fought tooth and nail and grown from something so little to become the third Batman.
He might have out grown his bright Robin costume, but he didn't outgrow the cape tugs or the pinch to his backside when they were patrolling - or, when he was patrolling, and she was meant to be between Star and Central. But when you could be to California in five seconds, taking a blink of a detour now and then didn't really phase the girl.
She was eighteen; he was twenty. Maybe he should have stayed in the Robin costume for a little longer, until they found a suitable sidekick for him, just like they had done with Irey. But it was Damian and he never outgrew his hardheaded, stubborn streak, the one that told him he was always right and he would never verbally admit anyone else was. He'd change his ways if they proved to be inconvenient, but he would never let someone know they were right in what they said.
He wanted to make his father proud, after all, and he could do that on his own. He didn't need anyone's advice or cajoling. He'd find his own way, through hell or high water. He'd done it before.
"What are you doing?"
He barely heard her over the snarls and the roaring of the thunder, threatening of the impeding storm that was already there in spirit but not in body. Damian barely heard her through the cowl and the wheezes of the man he had in his grasp, over his teeth grinding and fury pounding in his head.
"Damian!"
He didn't want to hear her.
"Damian!"
He turned his head, the thug still clasp in his gloved fingers, blood trailing from his knuckles and spattered on his face. Maybe his clenched fist loosened a little at the sight of her, eyes wide and horror on her face, maybe the rain finally hit and caused the body to slip from his grasp. Damian wasn't certain.
"This -" The choked noise in her voice turned her voice almost to gravel, rough and rocky. "This isn't Batman. Batman doesn't fight this way."
She reached up and covered her mouth, her shoulders tightening up in an effort not to wretch. Thunder hit, lightening flashing, and with that clap came the downpour.
"Batman doesn't kill, Damian."
"I'm not my father's Batman."
Just as quickly as the lightening struck, she was off.