Skin by Ally Wagner

Shapeshifters were wiped out two hundred years ago by their fellow preternatural beings. To prevent herself from reaching the same demise as her ancestors, Keira Quinn pretends to be a werewolf.
That is until she barely survives a brutal ambush.
With a thirst for blood and a short temper, she molds herself into a ruthless assassin. Nothing will stop her from getting revenge. She’ll hunt down the ones who attacked her and kill them one by one.
After all, what better way to assassinate someone than to impersonate the one they trust most?