Thomas is a young man held captive by WICKED who recently survived the trials of the Scorch. He is immune to the Flare virus and deeply distrustful of those in authority. Wrestling with intense feelings of betrayal, he refuses to have his memory restored by his captors, preferring to rely on his current instincts to survive and protect his closest friends. He routinely questions the motives of everyone around him, making him a difficult subject for WICKED to control.

Minho is a fiery and capable former Glader who refuses to let WICKED restore his memories. He acts as the emotional and physical glue for his small group of friends, stepping up as a fierce combatant and decisive leader when they attempt to break out of the compound. He relies on anger and aggression to mask his deep anxiety over the deteriorating state of the world.

Newt is the normally calm and collected former Glader who receives the devastating news that he is not immune to the Flare virus. Facing a future of inevitable madness, he becomes increasingly withdrawn, irritable, and desperate. He struggles to maintain his humanity while confined in the compound, ultimately choosing to separate himself from his friends to spare them pain.

Brenda is a resourceful WICKED employee who claims to be working against the organization from the inside out of a necessity to survive. She injects guards with sedatives to help Thomas break free and insists that she and Chancellor Paige are the only people he should ever trust, complicating Thomas's understanding of who his true allies are.

Teresa is a former telepathic companion to Thomas who firmly believes that WICKED has a righteous purpose. She advocates for the subjects to restore their memories, believing it is the only logical step forward. Her past actions in the Scorch have caused a massive rift between her and Thomas, which she struggles to bridge despite her cooperative attitude toward their captors.

Janson, often referred to by the subjects as the "Rat Man," is the Assistant Director of WICKED. Dressed in a sterile lab coat, he insists that all the torture the subjects endured was necessary to map the killzone and find a cure for the Flare. He pushes relentlessly for the subjects to undergo memory restoration, masking his intense pressure with false politeness and clinical detachment.

Jorge is a skilled pilot who aids Brenda and the Gladers in their escape from the WICKED compound. He is pragmatic and quick to act during firefights, securing a Berg aircraft to fly the group to Denver so they can seek out safe harbor and medical assistance.

Gally is a former Glader and rival to Thomas who has survived and relocated to Denver. Once thought dead after a violent confrontation in the Maze, he is now involved with the Right Arm, an underground group determined to bring down WICKED's operations completely.

Frypan is a former Glader who initially agrees with Thomas and Minho to refuse the memory restoration procedure. However, at the last moment, he changes his mind and separates from his friends to undergo the Swipe removal, seeking closure for his past.

Aris is a subject in the WICKED trials who shares a bond with Teresa. He readily agrees with her assessment that they should undergo the procedure to have their memories restored, placing him ideologically opposed to Thomas's group during the early escape planning.

Hans is an immune doctor living in Denver who formerly worked for WICKED. He possesses the specialized surgical knowledge required to remove the tracking implants from Thomas and his friends, operating underground to avoid a bounty on his head.

Vince is the authoritative boss of the Right Arm, an underground group actively kidnapping immunes in a strategic effort to infiltrate and disable WICKED. He does not believe a cure is possible and strictly focuses on military resistance over scientific endeavors.

Lawrence is a driver and operative for the Right Arm. He navigates a beat-up van through the dangerous, Crank-infested streets of Denver, displaying a reckless but necessary driving style to keep his passengers alive during sudden attacks.

Chancellor Paige is the highest authority within WICKED. Though physically absent in the early stages, her presence looms large over the subjects. She directs operations from afar, with Brenda insisting she is one of the only people Thomas should trust in a world of deception.

Charlotte is a former engineer for an arms manufacturer who now works for the Right Arm resistance group. She possesses the technical knowledge to remotely jam WICKED's weapon systems using a specialized device, giving the resistance a fighting chance.

Dr. Christensen is a WICKED physician tasked with analyzing the brain patterns of the subjects. He approaches the immunes purely as scientific data, operating with complete detachment from their humanity or suffering.

Dr. Wright is another medical professional working for WICKED. Alongside her colleagues, she focuses on extracting the final data required for the Flare cure, treating the subjects as vital ingredients in an experiment rather than living people.