Faith-Based Fantasy Fiction by Brian David Stansell
The Excavatia novels unpack the idea and theme of Christians learning to know God not just as Savior (at their birth conversion), but as walking in a surrendered and empowered intimacy with Him, letting him deal with the remaining strongholds by carrying Faith, Hope, and Love (symbolized by Eternal Virtue Stones) in making Him Lord of our Life. The villain groups in the story are representative of the allures that threaten to make Christians ineffective in their lives and called to ministry.