This is Sarah Davies. She's a fifth year Ravenclaw prefect, and she is an obsessive organizer. Seriously. She hsa a planner, and if she ever lost it, she might implode. She's also very smart, but despite that fact insists on studying every single day- at the properly schedule hour, of course.
But she is a pretty fun girl so long as you're not asking her to break the rules. She is a Davies, after all, so she's got a silly side to her, too!