Not surprisingly, Serret was my favorite character in A Wizard of Earthsea by Ursula K. Le Guin. A femme fatale is often also a victim, and that certainly felt true for Serret. She was married off to a much older man at a young age, and was almost disturbingly frank when we see her as a kid...I could never shake the feeling while reading it that Serret had seen too much for how young she was when she and Ged are hanging out in the woods and Ged gathers flowers or whatnot for Ogion.
Designing a costume for her was sooo up my alley. It's cold in Osskil and snowy, and the basic idea for Serret (who essentially is arm candy for her hubs, who she tries to control....but she's really bad at it) is that everything is covered up, but everything is on full display. But she has this rich scarlet underbelly of a cloak, because, you know, danger.