Dark Peril. Number 21 in series

Dominic of the Dragonseeker lineage - one of the most powerful lines the Carpathian people has - ingests vampire blood laced with parasites in order to infiltrate the heart of the enemy camp and learn their plans. This is a one-way mission. He plans to get in fast, relay the information to the leader of the Carpathians living in the area and go out fighting - an honourable way to end his life. Solange Sangria is one of the last of the jaguar people, a royal pure-blood.
Her people, once many, are now nearly extinct. She has long been alone fighting to save the remaining women who are able to shift from the hands of Brodrick the Terrible, her own father who slaughtered everyone she loved. Wounded, weary, she plans one last battle, hoping to stop the man who has made an alliance with the vampires, accepting she will not come out alive. They are two warriors who have lived their lives alone.
Now, at the end of their time, they find each other, a complication neither sees coming.