By Right of Blood - The Demon of Stonehaven, #1

William Fylbrigge is ill prepared to claim what is his by right of blood and his place among the powerful clan he has been born into. His older brother Thomas doesn't want to share what he thinks is rightfully his, secretly arranging to have the young lad killed in a convenient "accident." William could lose everything, including his life. Sean Wilbrun, the son of a common groomsman, transcends the barriers of his class and station when he is elevated to the esteemed ranks of guard for Lord Edward, Duke of Stonehaven.
His first assignment, however, is not to wield a sword to protect his duke, but instead to attend to the newly arrived foster son. William and Sean soon form an unlikely duo and a lasting bond as together they face Thomas' accusations of murder and treason.