The Last Wizards’ Ball by Charlaine Harris

Lizbeth Rose’s sister Felicia attends the Grand Wizards’ Ball, and as one of the most powerful—and beautiful—death wizards in a generation, she is highly sought after as one of the belles of the ball.
However, war and violence are on the rise in Europe as German and Japanese wizards are also courting Felicia…and some are refusing to take no for an answer.
As the façade of genteel wizard society turns deadly, Lizbeth must learn to not only protect her sister, but also navigate the arcane world that is pulling her sister and husband into a dangerous dance with death that could change the world as they know it.