Having a Slytherin bug one of her fellow Gryffindors was enough. But knowing that the Slytherin was her brother was enough to set Damitrius off, although she tried to keep her cool so she didn't do anything rash that would cost her House some points. "Damien, you know full well that there is no 'field trip' going on." she said, her eyes narrowing. Her brother was annoying, that was it, her brother was just annoying to her, and to others that wouldn't be mentioned.
"Although I can surprised to see you here." she said. "I didn't think you knew how to get here." she smirked. She put her hands on her hips and sighed. "Look Damien, why don't you just run along back where you came from, and leaves these two alone?" she continued smirking at him. She knew there was no way that he would just give up and leave, not in his character, but she would not stand for a fight there.
"I, personally, don't want to fight with you." she told him. "But I won't stand by while you, think big of yourself because you are a Slytherin, and you bother others." she hissed at him. "You might be able to get away with things like this at home, but while we're here I won't let you. And... Alexis... isn't here to protect you anymore." she said, her eyes narrowing further at her mention of their older sister.