The Knights of Arrethtrae is a series of six books written by Chuck Black. It is a spin-off of The Kingdom Series, also by Chuck Black, and depicts events that occur during the same time period as books three to five-Kingdom's Edge, Kingdom's Call, and Kingdom's Quest-of that series.
Description[]
The Knights of the Prince are recruiting and training all who will follow the Prince as they wait for His return. During these years, brave knights rise up and take the story of the Prince deep into the heart of the kingdom and to the far reaches of the land. They encounter great adversity and peril as they fight against many strongholds established by the Dark Knight as well as those influenced by his power. Each title allegorically teaches a biblical principle such as loyalty, compassion, courage, humility, and faith while warning against the tools of the devil such as rebellion, greed, doubt, and apathy.
Synopses and sample chapters can be found here