Raven's Shadow — Patricia Briggs

For many years, the city of Colossae was a haven of magical study. As generations of wizards pushed the limits of their abilities, an evil entity was unleashed that could only be contained by the sacrifice of their city. From the ashes of Colossae, the Travelers emerged--roaming the world to ensure that the Stalker would remain imprisoned forever...

Seraph is a Raven mage and among the last of the Travelers. Unwelcome among those who fear magic, the wizard clans have been decimated by the very people they've sworn to protect. But Seraph is spared a similar fate by the ex-soldier Tier--and together they build a life where she is no longer burdened by her people's responsibility.

But now Tier is missing--or dead--and Seraph's reprieve from her duty is over. Using her magic to discover her husband's fate, Seraph realizes the Stalker's prison is weakening--and only Seraph can fulfill her ancestors' oath to protect humanity from destruction...