Cora listened to Erin's explanation about the guys. "Yes, I'm Cora." And then Derek jumped in with his remark. "I can start if I want to. You shouldn't be here," she warned. Since she wasn't sure if he said anything to Erin and/or Stiles, she kept the fact that Derek was a human to herself. For now.
She rolled her eyes. "I heard that," she said as she glared at Stiles. But her attention went right back to her brother. "I don't need you to look out for me. I think I can deal with the full moon all on my own. I've been doing it long enough."