The Coven of the Crown (смешанная)

As the last remaining Sorceress in the wizarding world, and the chosen heir of Morgana LeFey, Hermione is fated to lead a coven—three witches bound to her by ancient oaths: the Protector, the Healer, and the Voice. Without them, her power will turn inward. Devour her. Drive her mad.
Prophecy says she will call for them when she accepts her legacy, but by end of her first year at Hogwarts, Hermione realises who her bonded three are—and she's horrified. Intrigued. Uneasy in all the right and wrong ways.
Because it's the Black sisters.
Bellatrix. Narcissa. Andromeda.
What follows is years of tension and slow-burning temptation. Hermione doesn't mean to fall for them, but when they're together, her magic sings. And the world tilts. And she just can’t help it.
Meanwhile, darkness stirs again—the kind that once shattered Avalon and tore Morgana's own coven apart. As Voldemort rises, so does something older. Wilder. Hungry.
Hermione's ready to end the war. To break the curse. And to live a life of peace with her coven the way Morgana once dreamed. But all magic demands sacrifice. The question was never if she was strong enough to win. It's what she'll have to lose to do it.