20Sirius Black was her Favorite Cousin
Given her extremely close ties to the xenophobic Voldemort, Bellatrix Lestrange’s feelings regarding wizardly blood purity should be obvious. She was more than willing to cut ties with any family members she believed to have married outside of the Wizarding World, and she took these beliefs to a major extreme
when she ended the life of her niece Nymphadora Tonks.
She wasn’t as cold hearted as she may have seemed, however, as she was very closed to most of her extended family before their apparent treachery. Lestrange is famous for defeating Sirius Black during a battle at the Ministry of Magic in Harry Potter and the Order of the Phoenix, but she once held him in very high esteem.