Oath of the Brotherhood — C.E. Laureano

In a kingdom where the Old Ways hold fast and a man's worth lies entirely in his skill with the sword, Conor Mac Nir is a scholar, a musician, and a follower of the forbidden Balian faith: problematic for any man, but disastrous for the son of the king.

When Conor is sent as a hostage to a neighboring kingdom, he never expects to fall in love with the rival king's sister, Aine. Nor does he suspect his gift with the harp (and Aine's ability to heal) touches on the realm of magic. Then his clan begins a campaign to eliminate all Balians from the isle of Seare, putting his newfound home in peril and entangling him in a plot for control of the island that has been unfolding since long before his birth.

Only by committing himself to an ancient warrior brotherhood can Conor discover the part he's meant to play in Seare's future. But is he willing to sacrifice everything―even the woman he loves―to follow the path his God has laid before him?