Dark queen : a Jane Yellowrock novel
(Book)

"As Enforcer to the vampire Master of the City of New Orleans, Jane Yellowrock stakes her reputation and her life on keeping her territory safe. But Leo has been issued a blood challenge by the emperor of the European vampires, who seeks to usurp all of his power and possessions. If Leo loses the match to the death, the city will be forfeit, and the people of New Orleans will suffer the consequences. Jane can't let that happen. Preparing for the duel requires all of Jane's focus, but with so much supernatural power in play, nothing goes according to plan. She has to rely on herself and the very few people she knows she can trust to stand and fight. Only two things are guaranteed: nothing is sacred, and no one is safe." --,(Source of summary not specified)