An empathetic and observant firefighter from South Dakota, who moves to California, becomes close with Kristen, and balances his desire for a family with the realities of Kristen's condition.

Kristen's best friend since high school, nurturing and supportive, who offers a stark contrast to Kristen’s personality and provides her with emotional support.

Josh's best friend and a fellow Marine veteran, who becomes a catalyst for Josh's move to California and plays a pivotal role in Josh and Kristen's lives.

Kristen's long-distance Marine boyfriend at the novel's start, whose absence and differing life goals highlight the contrasts between him and Josh.

Kristen's mother and a respected lawyer, whose critical and cold demeanor affects Kristen’s self-worth and influences her emotional resilience.