There isn't a single wizard or witch in the wizarding world who doesn't know and fear the name Lestrange.
Katerina Lestrange, the great granddaughter of the evil witch Bellatrix, always thought she deserves the best. As an only child she was always given everything she wished for and that is likely what shaped her to be the selfish, self-centered girl she is. She was born and raised by a couple of pure blood wizards, death eaters, who hated mud-bloods and muggles and that of course affected her as well.
Katerina is witty, sarcastic and somewhat evil but even though she can be a massive bitch she does have some good qualities. She is loyal, clever, beautiful, funny, and despite how hard she tries to hide and control it, she does have feelings, she gets hurt and upset yet she chooses not to show it.
Katerina has reddish brown hair and blue eyes. She has a lovely thin body and she never really struggled with her appearance and self-esteem, she's naturally beautiful but she likes to show, through her clothes and make up, the dark side in her.
Considering all her other qualities it makes sense that she loves being wanted and the center of attention. She loves being chased after, she loves playing games.
Given her family history the dark arts has always interest her and that's one of the main reasons she wanted to go to Hogwarts so badly.
She puts on a show to please her teachers and parents but all she truly cares about is learning dark magic and having a nice time, even –and especially- if it means getting others in trouble.
She knows she'll end up in Slytherin. It's in her blood. She belongs there.