Clara was born in York, England to an old and fairly traditional wizarding family. Her mother is Nora Thornheart, a socialite who has never worked a day in her life; and her father is Lachlann Thornheart, a stern scottish man who works in the Spirit Division of the Ministry of Magic. Clara's mother dotes on her but can be a litlle controlling, even going as far as to control what she wears. She rarely sees her father, who is often busy at work but they share an affinity for the spirit world and fascination with the past.
Clara is a relitively quiet girl who spent a lot of her time growing up isolated, reading the various myths and legends of the wizarding world from books out of her father's library. She has a passion for the past and loves to immerse herself in history, often finding herself daydreaming about life hundreds or even thousands of years ago.  
Clara has curly red hair and and her pale skin is frosted with freckles.  She is of a slightly below average height and very thin, almost frail-looking. If it weren't for her bright red hair, she would have an almost ghostly appearnce herself. She tends to dress in smart and more formal clothes, but these are her mother's choices and not her own.