Mackenzie is a pragmatic father of five who lives in Oregon. Having endured severe trauma in his youth at the hands of his abusive father, he struggles to maintain a deeply personal faith. He carries an immense emotional weight, referred to as the "Great Sadness," following the disappearance of his youngest daughter during a family camping trip.

Papa is the name Nannette uses for God, and she appears to Mackenzie primarily as a warm, joyful African American woman. She acts as a motherly figure who seeks to help Mackenzie process his grief and anger. She listens to funk music while cooking and emphasizes that relationships should be built on love rather than authority.

Jesus is a Middle Eastern carpenter who forms part of the trio Mackenzie encounters at the shack. He is deeply relatable and approachable, quickly putting Mackenzie at ease through casual conversation and shared tasks. He views humanity through a lens of mutual submission and actively questions human power structures.

Sarayu represents the Holy Spirit and speaks in ways that emphasize action and verbs over static nouns. She possesses a mystical quality, often appearing unexpectedly to offer Mackenzie new ways of perceiving his emotions. She tends a messy garden that represents the complex nature of the human soul.

The Little Ladykiller is a notorious serial killer who targets young girls. He leaves a signature ladybug pin at his crime scenes and is responsible for the devastating trauma inflicted upon the Phillips family.

Nannette is Mackenzie's wife who works with terminal cancer patients. She maintains an intensely personal spiritual life, referring to God affectionately as "Papa." Her deep faith contrasts heavily with her husband's lingering doubts.

Missy is Mackenzie and Nannette's youngest daughter. She is an inquisitive child who closely examines the stories she hears, often asking questions about sacrifice and love. Her sudden abduction from a picnic table acts as the central tragedy that devastates her family.

Kate is one of Mackenzie's teenage daughters. Following the tragedy at the campground, she withdraws into herself and struggles heavily with emotional distress. Her parents worry extensively about how to reach her.

Josh is Mackenzie's son who nearly drowns when his canoe tips over on the final day of their camping trip. His accident draws his father's attention away from the campsite during a critical window of time.

Willie is Mackenzie's longtime friend who frames the narrative by writing down the story of the "Great Sadness." He lends Mackenzie the vehicle needed to travel into the wilderness for the weekend.

Sophia is a beautiful, regal woman who personifies divine wisdom. She forces Mackenzie to examine his own tendencies to pass judgment on others and confronts him with impossible choices regarding his own children.

Mackenzie's father is a man who struggled with alcohol addiction and subjected his son to severe physical abuse. His cruelty drove a young Mackenzie to run away from home, leaving lasting emotional scars that affect his adult view of fatherhood.

Jon is one of Mackenzie and Nannette's adult children who has grown up and moved out of the family home in Oregon.

Tyler is another of Mackenzie and Nannette's adult children who no longer lives at the family home.