A kind-hearted, risk-taking resurrectionist with gray eyes and dark hair, who works to support himself and becomes Hazel's romantic interest. His love for Hazel influences her development and actions throughout the story.

A renowned and skillful surgeon in his mid-forties, with blondish hair and deep dimples, who serves as Hazel's mentor and has ambitious medical pursuits. His actions significantly impact the novel's themes and the protagonist's journey.

Hazel's self-absorbed and possessive cousin, he is initially described as nice enough, with clear skin, but his true nature as antagonistic becomes clear, impacting Hazel's personal life and choices.

A pragmatic surgeon with a vulture-like appearance, characterized by his eyepatch and bloodstained coat. He has a conflictual relationship with Hazel, initially preventing her from pursuing medicine by excluding her from his classes.