Justine goes through many changes, extreme and subtle, within the books and throughout the series.
In Grave Peril, when Harry Dresden first meets Justine outside Bianca St. Claire's ball, she's wearing a flower petal costume that barely cover her and baby's breath in her tumbled mass of black hair. She had a face that made her seem sweet and lovely. She looked like she was on something.
Later, captured by the vampires, she was a dirty gaunt mess with feral, unsettling eyes. She says she's always like this only Thomas Raith "makes it quieter", she doesn't have the control other people have. Leonid Kravos, possessing her, says it's her ranting emotions that make the White's love her so much, she's mad with emotion.
In Blood Rites, at the beginning, she appears to be not quite drinking age, dark hair, dark eyes, a little taller than average. She wore a white sweater and a short black skirt over a lot of leg, she was a knockout. Raith reacts to seeing her with relief like a sailor lost at sea spying land.
Later, after Justine barely survived Raith's feeding, Bobby has to carry her. She has silver-white hair with some grey, her limbs hung limply, and very thin, her skin was unwrinkled, her pallor was near death.
In Turn Coat, in an early scene at Zero, she has a girl-next-door face, her silver-white hair was held up in a bun by chopsticks and she wore a full white form-fitting rubber cat suit that covered almost everything, including her hands. Later she has her hair in a long tail and is wearing a grey business suit.
Justine is a beautiful slim girl, who is in love with Thomas Raith. Raith loves her back, but true love burns him, so they can never be together. To Raith, she appeared to be just food when she was originally introduced in Grave Peril, but since then, she has nearly died, been restored.
Justine, being close to Lara, has been working undercover for Harry Dresden getting him information on the White Court's activities from time to time, to help with the new Paranet Dresden puts together.
Word of JimEdit
Thomas and Justine’s relationship is really weird. I know what the relationship is in my head like right now. They’re actually happier now than they’ve been in ever. But it’s all happening behind the scenes and nobody can see because Thomas has to have his bad ass vampire face on whenever he’s in public. But when they are alone together, nothing else going on, they’re like totally cute. Justine wears like these grownup version of footie pajamas so that she can snuggle up next to him on the couch and watch TV without actually burning him. They don’t have like a normal relationship or anything like one, but they’ve kinda adjusted, they’re fairly happy. You don’t go around letting the other vampires go ‘Oh how cute.’ I’ll have to get to that one of these days, Harry doesn’t see that.— Jim Butcher on Justine and Thomas Raith’s relationship.