Content Warning: This section of the guide discusses physical abuse, sexual assault, and self-harm.

Casteel serves as the novel’s narrator and protagonist and assists in developing all major themes. Cas is Poppy’s love interest. In the present timeline, Cas and Poppy married recently and are the newly crowned King and Queen of Atlantia. Over 200 years old, Cas has black hair and golden amber eyes, and Tawny and Poppy agree Cas is sexy and an “improvement” to look at. He is an Elemental Atlantian, one of the oldest and most powerful bloodlines, and he has the magical ability of “compulsion,” or the ability to make others do and say whatever he wants. Incredibly fast and strong, Cas turns brutally violent on the battlefield. He takes pleasure in hurting others who participate in unjustifiable evil.

Vikter finds Cas to be “arrogant and cocky. […] And a smartass” (217). Cas is often the first to admit his faults; he can be overly confident and intimidatingly forward, especially with his sexual advances. He fulfills the “bad boy” cliche and foils Poppy’s purity as an untouched Maiden. Cas is hotheaded, particularly when anyone threatens Poppy. As he gets to know Poppy, Cas undergoes a significant character change.