Immune from the Flare, Thomas is removed from his home at five years old and taken to WICKED headquarters for testing. He emerges as the organization's top candidate to save humanity. At 15 Thomas's memories are erased. He's sent into the Maze, which he quickly solves, helping many other Gladers escape. Thomas spends the series fluctuating between anger at being a human test subject and desperately wanting to help find a cure. At the end of the series, Thomas hopes to escape WICKED control by escaping to a safe zone through a Flat Trans at the end of The Death Cure.
Mark rescues Deedee in The Kill Order after her religious cult village abandons her because they think she called the devil. When Mark realizes Deedee is immune to the Flare, he gives his life to ensure her transport to the government safe zone in Alaska. WICKED changes Deedee's name to Teresa and uses her in a series of experiments in search of a cure. Because Teresa remembers her traumatic childhood, she remains devoutly faithful to WICKED and its mission. She manipulates friends, including her best friend Thomas, to ensure their participation in WICKED trials. Teresa has the ability to communicate telepathically and excels with computers and technology.
Forcibly taken by WICKED as a child after the government shoots his parents, Newt, like Thomas, Minho, and Teresa, is raised in solitary confinement. His life is filled with tests and experiments. Newt is a control subject, meaning he is nonimmune to the Flare. His immunity makes him more disposable than other test subjects. Being separated from his little sister devastates Newt, and he tries to commit suicide a few weeks after being sent to the Maze. When he contracts the Flare during The Death Cure, he begs Thomas to kill him.
Minho arrives at WICKED headquarters just like the rest of the test subjects—forcibly removed from his home after testing immune to the Flare. Minho quickly emerges as an aggressive, defiant kid who regularly plots to escape WICKED and run to freedom. He proves himself to be a diligent Runner in the Maze, never slowing or stopping his work, as well as a loyal friend to Thomas. Minho is described as Asian.
Mark stars as the hero of The Kill Order, which takes place 13 years before The Maze Runner. Mark survived the sun flares underground and quickly partnered up with Alec to find safety in the Lincoln Building in downtown New York. After WICKED starts shooting settlers with the Flare, Mark and his friends travel to a government safe zone, saving Deedee along the way. When Mark learns Deedee is immune to the Flare, he sacrifices himself, ensuring she alone reaches the safe zone.
As a wartime veteran, grizzly Alec is the most prepared for life in a postapocalyptic world. Middle-aged Alec is no longer in his physical prime in The Kill Order. But he manages to exhibit constant strength, planning, and other survival skills in many dangerous situations. For example, Alec successfully uses a grappling hook to fell a Berg, steals and navigates encrypted maps, and mercy kills two of his friends (the Toad and Lana) to prevent them from suffering. At the end of the novel Alec contracts the Flare and sacrifices himself by flying a Berg into the Flat Trans to keep Deedee safe.
Brenda is a double agent. She works for both WICKED and the Gladers, to whom she has become attached, specifically Thomas. Brenda is described as an older teenager who begins working as a location scout for WICKED and later as a surgical nurse. She pretends to be a Crank in The Scorch Trials to monitor Thomas, to whom she is strangely affectionate. The novels hint at a deeper relationship between Brenda and Thomas, although it's never fully explained. Brenda helps Thomas escape from WICKED headquarters in The Death Cure, and he realizes she can be trusted.