Ruthless (Eredia Academy Book 2) by Gemma Black

Indigo Jalen has blood on her hands. She makes no apologies for it.
 
After years of working in the shadows, leaving bodies behind, she never expected her identity to be exposed. Especially not to them.
 
The Sinclairs thought they had her cornered and under their thumb with their blackmail scheme. Now they know exactly who she is—and what she's capable of. Their options are simple: kill her for her deception, or admit she's the first woman who's ever outplayed them.
 
The Sinclairs didn't build their empire by showing mercy. But something about their would-be victim calls to their darker instincts. Something that has nothing to do with revenge.
 
When the lines between what was and what will be blur, Indi must make a choice. Work with the men who tried to destroy her, or walk away from the only people who might understand her brand of darkness. And maybe give her everything she never knew she wanted.