Hannah
Ah, another of her father's favorites who can use insidious backdoors to get through her assortment of magical wards. At least it wasn't her other little sister punching the door down again, no matter how cute she was. That's about what went through her head the moment she noticed someone had gotten into her room, right before she realized what they were saying and how they looked while saying it!
Hannah's mouth gaped open for a moment at the sight of - "Magical Girl Milky Spiral Seven! Ahahaha, oh, that's a good look!" She'd leaned back to get a better look at her intruder's cosplay, and then hopped off the couch with a flap of her wings. "Hold on, hold on-!"
She didn't even have to change her glasses, just shorten her hair up a bit, adjust her eye color, some facial features, a little breast reduction, and then a snap of the fingers and a flash of hellfire left her in a rather complementary magical girl outfit of her own for the occasion, right down to having a hat. Then, she put on a stern expression of embarrassment. "You can't just appear in other peoples' rooms, no matter how great your taste in anime is, onee-sama!"