A/N: I put "the Ministry" for Andromeda's loyalties because this takes place when Bellatrix is 16, Narcissa is 13, and Andromeda is 11. So therefore Andromeda didn't know about the Order.
Disclaimer: I don't own Harry Potter.
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Bellatrix Black was the oldest of the three Black sisters and the most serious. She had long, curly hair as black as night, dark eyes, and a pale, hollow face. In her own way she was very attractive. She generally was harsh and rigid, and by no means possessed a conscience. She was always sincerely loyal to the Dark Lord and had no boundaries when it came to him asking things of her.
Narcissa Black was the middle child and the least serious. Her thick, straight blonde hair fell to her shoulders, slightly curling inwards at the bottom. Her eyes were a piercing gray, and her skin was a moderate shade of tan. She was definitely beautiful; almost no boy could resist her. Her loyalties were never specifically set to anyone, and she definitely had boundaries. She would do anything for the people she loved, though.
Andromeda was the youngest and definitely the most different. She had straight chocolate brown hair that was a little bit past her shoulders. Her eyes were the same color as her hair, and like her oldest sister, she had pale skin. Her face, unlike Bellatrix's, was full and not hollowed. She had a simple beauty to her. Her loyalties definitely were with the Ministry. She had gotten in trouble for defying her parents, but eventually she didn't even care.
When they were young they had played together in peace. As they got older, they started to drift apart, especially Andromeda. By the time they were all in school at the same time, you just barely tell that Andromeda was Bellatrix's and Narcissa's sister.
Bellatrix grew up and married a respectable pure-blood man. The Lestrange family had been family friends with the Blacks for quite some time and it wasn't that much of a surprise when Bellatrix and Rodolphus announced they were engaged. Both sets of parents were so proud to see their children marry well.
Narcissa grew up and married a respectable pure-blood man as well. The Malfoys hadn't been as well acquainted with the Blacks as the Lestranges had, but they were still a good and wealthy pure-blood family to marry in to. That was good enough for Narcissa's parents.
Andromeda, however, grew up and married a Muggle-born man. In the Black family's eye this was intolerable, unacceptable. It simply could not be done. They told her it was either him or the family. Well, Andromeda made the obvious choice in choosing him instead of her pure-blood mania fanatic family.
Her parents had been absolutely furious about the choice. They immediately burned her off of the family tree. Bellatrix had been just as furious as them, if not more. Narcissa hadn't really been furious but she wasn't proud of her sister's choice. However, she did keep some civil contact with her.
That little contact disappeared, though (not that either one cared). Bellatrix didn't even really communicate with her parents anymore because of her becoming a Death Eater (which they were immensely proud of). Narcissa had been the only one who still kept in touch with them.
It really was a tragedy how the sisterhood of the three Black sisters ended.