Vow of Thieves explores the power of bonds that extend beyond blood. The novel juxtaposes multiple families and communities, showing that characters find profound strength within these connections. For instance, the Ballengers, a large clan steeped in history and legacy, starkly contrast Kazi’s small found family, which comprises of Wren and Synové. Despite how different these families are, their various family members share similar relationships grounded in loyalty. However, family is not the only source of strength in this novel; community emerges as another indomitable force. The novel emphasizes that human connections—whether chosen or determined by birth—are stronger than violence or weapons.

Kazi prioritizes family and community from the beginning of this novel, which shows her character growth from the previous book in the series. In the previous novel, Dance of Thieves, her grief and trauma over her mother’s kidnapping prompted her actions. However, in this novel, she puts her anger aside to focus on what is best for Jase’s family, thinking of them as her own, and proving that Kazi is fully capable of making unselfish decisions and prioritizing their wellbeing. At the beginning of Vow of Thieves, Kazi worries about melding with the Ballenger clan after her marriage to Jase, telling him: “I’ve never had a family before, Jase.