Thank you, compound complex.
As for backstory, this novel has had numerous sources of inspiration. The infamous "Summer of Sparlock" in 2012 caused me to begin to think about some of the themes I would later use in the book. As I did further research, I learned of how many of these ideas have permeated our myths, legends, and symbolism throughout history.
I discovered a purple-clad rebel from Jewish legend who reminded me of Sparlock the Warrior Wizard. This rebel also appears in the Bible and Gnostic writings and has had an important influence over significant historical events such as the Protestant Reformation. I even discovered that two of the characters associated with his story were named Caleb and a Sophia. I couldn't help but to have some fun with these odd coincidences.
Setting the story within the context of a multiverse allowed me to leave the existing mythology of Sparlock mostly unchanged while presenting dramatic events in a parallel world that expand upon those themes. However, the multiverse isn't just a plot device. The idea of traveling to other realms or worlds is integral to many of the myths and legends that appear in the novel.
In addition to exploring certain aspects of cultural and religious history, the three novels of the Sparlock Trilogy will take a sequential look at the history of the Jehovah's Witnesses. The first book focused on the predictions of the Millerites and Charles Taze Russell. The second book will introduce Joseph Rutherford, and the third book will include later developments in the organization.
Well, that's a general overview. I also did an author interview where I discussed the backstory of the novel in greater depth.