It's hard to say for certain. Sometimes stories like 'La Esclava Blanca' combine real-life elements with fictional creations to make an engaging narrative. You'd have to do some research to know for sure.
The main character is probably Father Amaro. There could also be characters such as the people in the community he serves. Maybe there are other religious figures or local townspeople who interact with him and play important roles in the development of the plot related to the crime in the novel.
One possible main theme is the power dynamics and corruption. In this novel, it might show how power within the church or society can be misused, leading to various crimes and moral downfalls. This exploration of power and its abuse could be a significant aspect of the overall theme.
The book contains stories such as those of heroic quests, magical encounters, and personal growth. They all contribute to the overall charm and depth of 'El Libro de la Vida'.
I don't have enough information to say for sure. It could be fiction, or it could have roots in reality that have been adapted or exaggerated for a particular purpose.