A Sin So Pure by G.B. Bancroft

Death is a wicked kind of magic to wield.

Nora is a soul-stealer, one of the few fae who can kill with just a touch. Taken in by the leader of House Pride after her parents’ murder, Nora’s been groomed into the perfect weapon: a killer who can lead.
And when the opportunity to seize power from her manipulative adoptive father arises… well, she’s not one to look a gift horse in the mouth.
A year later, Nora and her Second, Josie, are ready to expand House Pride’s influence in both the Unseelie Court and the Human Realm. Nothing will stand in their way—except for the person attacking their House. Nora is no stranger to bloodshed, but this isn’t a run-of-the-mill raid by exiled fae; this attack is personal, mirroring the tragic night her parents died.
Nora vows to find the fae responsible, but soon realizes that the closer she gets to the culprit, the more she risks revealing a secret that could ruin everything she’s built: her House, her title, and the love she’s been cultivating with the leader of House Lust, Imogen.

But the thing about Nora is that no one threatens her family and lives—and there’s no sin quite as sweet as revenge.