Thousand Autumns, book 3
Meng Xi Shi

Despite the sting of Yan Wushi's betrayal fresh on his heart, Shen Qiao rushes to save him from certain death only to arrive a moment too late-or so it seems. As rumor of Yan Wushi's demise spreads far and wide, the winds of change stir across the land. Meanwhile, Shen Qiao seeks to heal Yan Wushi's grave injuries, and realizes that his understanding of the Demon Lord runs only skin-deep. Yet fate does not allow the pair to remain idle for long.

When an old friend reveals his true nature, Shen Qiao and Yan Wushi have no choice but to aid him on a perilous mission. Only this time, humans aren't the only monsters to fear.