Realm of Night — Sarah C.E. Parker

After an act of revenge puts him in trouble with the law, 17 year old Seth had a chance run-in with a young warrior named Viera and gets thrown right into the middle of a decade-old war between the Empire of Nocturne and the acolytes of the Light that oppose them. Hunted, desperate, and with nowhere to turn but to each other, Seth and Viera set off on a quest to deliver a powerful talisman known as the Xerkzes stone to Viera's home city before the empire can reclaim it and use it to wreak havoc once more.