Legacy of the Demon: Demon Novels, Book Eight (Kara Gillian)

Sidelined demon summoner Kara Gillian has her hands full when dimensional rifts allow demons to cause widespread panic and destruction on Earth. These aren't the human-tolerant summonables she's known before, but demons from the far reaches of the demon realm. 

Add three demonic lords with conflicting ambitions to the mix, and Kara has the perfect recipe for global disaster.