My name is Lex, and this is Cordelia Selwynn. She's a fifth year Slytherin prefect. She's actually pretty nice as far as Slytherins go. Though she is from an old wealthy pureblood family, Cordelia is ambitious and independent and wants to achieve things through her own merits rather than because of her family or wealth. She also believes that her social station imposes obligation to others, so she's fairly generous with her time if someone asks her for help.
Of course, being from Slytherin house, her kindness isn't simply for the sake of being kind - she believes it will advance her socially and help her form a fairly impressive network of connections in the long run.
She's got a perfectionist streak a mile wide, and is downright obsessive about getting top marks. The main times one will see Cordelia being anything but pleasant or at least polite is when she's just gotten a bad mark on something. She expects the best of herself, and when she isn't achieving the best, she gets rather surly.
So....friends, enemies, crushes, acquaintances that keep running into each other but rarely talk, etc. I'd love to hear how your characters might interact with her. :)
I can be reached on AIM at Katana Maid or by email at evil_wild_lex at yahoo.com