At the Border of Destiny by C. Quince

Murad is an Imperial Messenger, and he has a secret… He's a witch.

On a visit to the foreign court of Mercia in Britain, he has a vision of the crown prince, Aaron, in serious trouble.

In his desire to save Aaron's life, Murad becomes entangled in Mercia's political strife, border disputes, and rising Paganism.

At the heart of the conspiracy, Murad encounters a powerful blood witch who has plans to sow division in the land.

Her magic is too strong for Murad on his own, so he seeks out new allies in two very different witches: a green witch, and a Viking seer.

As lines are drawn in the sand, both at court and on the battlefield, Murad stands with Aaron, bolstered by their allies. Together, they can unite Mercia for good.