End of the Sword by Rebecca Grey

Never trust the voices.
Queen Ambrose is plagued by voices she can’t identify. When they tell her to jump she jumps and when they tell her to run she runs. Fleeing into the arms of her eldest sister, Ophelia, she is reminded that some games cannot be won.
While the queens play their games, Ace, Shelby, and Rehan move through the capital cities following leads that turn into dead ends until they’re left with only one choice: free the witches. War has started and it’s going to take blood to come out victorious. Are they willing to do what it takes?
Victory comes at a cost. Sacrifices must be made.