The novel explores the complexities of family legacies, especially within a community marked by historical trauma. The Trudeau twins grapple with the weight of their family's past, including the loss of their father and the curse on their mother. Their journey becomes a quest for understanding and healing as they confront the secrets and sacrifices made by generations before them.

Magic in 'Blood Debts' is a double-edged sword, capable of both healing and destruction. Cristina's decision to abandon magic stems from a traumatic event, showcasing its potential for harm, while Clement finds solace and strength in his magical abilities. The story highlights the responsibility that comes with wielding magic and the difficult choices it forces upon individuals.

The massacre that haunts New Orleans serves as a constant reminder of the deep-seated prejudice and social injustices faced by the magical community. The novel tackles themes of racism, discrimination, and the fight for equality, intertwining them with the central mystery and the characters' personal journeys.