Margaux is a half-breed. She has brown and curly hair most often, although her mother sometimes smoothes it. Her hairstyle is a simple square, above the shoulders. She has very dark eyes, a rather big nose, luscious and pinkish lips. Her look is suspicious and mocking. She's 4'6 for 35 kg at 12 years old. Her figure is rather thin.

Margaux is a haughty and contemptuous girl. She's not very sociable and that suits her very well. She can be hurtful because she's very frank. She's ambitious and calculating. She often harshly judges the people she sees for the first time. She's not very fair and does not like to lose. It's also sneaky in achieving her objectives.

Margaux was born on December 2, 2009 in London into a Pure Blood family. She has two brothers, Thomas and Jake, aged 25 and 19 respectively. His father, Frank, is a 44-year-old former Slytherin and his mother, Clotilde, a 43-year-old Ravenclaw. Margaux grew up in a witch family, she knows nothing about the Muggle world. His mother took care of teaching him to write, read, etc. and his father taught him witch culture, adding his little grain of salt about the Muggles. Because, yes, Frank is one of those pro-Pure Blood sorcerers. He educated his children in that notion. He would be ashamed to have his daughter go to Hufflepuff. Clotilde is also a Pure Blood, but most of his father’s family is French. She grew up with the same ideas as her husband. Thomas and Jake both finished their schooling at Hogwarts, in the respective houses of Gryffindor and Slytherin.

Margaux’s first act of magic came as she played hide and seek with her brother Jake. He was walking on a carpet, he was going to find her, so she unconsciously lifted the carpet and dropped her brother. Her family was very proud of her. She was 8 years old.