"Chain of Thorns" explores the multifaceted nature of love and the sacrifices it demands. Cordelia's love for James is tested like never before as she grapples with her growing feelings for Matthew while bound to Lilith. The novel delves into the complexities of love triangles, highlighting the pain of unrequited feelings and the courage it takes to let go. Throughout the narrative, characters face agonizing choices, forced to sacrifice their own happiness for the greater good of those they love.

Family secrets and the weight of legacy take center stage. The revelation of Belial's connection to the Herondale lineage throws the family's loyalty into question, forcing them to confront a dark history. Characters must grapple with the sins of their ancestors and find the strength to break free from the chains of the past to forge their own destinies.

Even in the darkest of times, hope flickers. As London plunges into chaos and the Shadowhunters face insurmountable odds, the novel emphasizes the importance of resilience and unwavering belief. Friendship, loyalty, and love emerge as beacons of hope, reminding us that even in the face of despair, the human spirit can endure.