Liam Plecak initially appears as a rather quiet and reserved person, later becoming unstable due to continuous trauma from competing in ONE. His mental state would deteriorate the longer the stayed in the competition, reaching a point where he experiences hallucinations. Liam formerly worked an office job in San Francisco, California with his co-worker Owen at GTIAB. However, after he was presumed dead by the police due to his seven-month-long disappearance, he is now unemployed, with his office building having been put up for lease. Liam has a lot of empathy for the other ONE contestants as he wishes that no one should go through the pain that he experienced in the hands of Airy. He's very cheerful and playful when talking with his friends, but appears to be somewhat lonely, as it took over a month for him to be reported missing. He's the one who managed to bring Airy and everyone else back where they belonged.

Bryce Hansen is quick to anger and can be quite grumpy as he frequently complains. He is uninterested in the competition, so much so that even with promises of a wish for anything he wants, he continues to be dead set on going home. Bryce doesn't hesitate to stand up for himself, as he's shown to frequently argue with people who bother him. However, Bryce has a softer side to him. Although he's shown to be easily irritated by Liam, he still cares for his well-being, preventing him from partaking in dangerous situations and motivating him in times of need. He is also very jumpy and easily distressed. He has thalassophobia. He works a 9-5 at a burger restaurant.

Amelia Euler generally has a calm and down-to-earth disposition, and it is still preserved during her time in The Plane, despite the unorthodox circumstances. She cares for her fellow competitors, being worried for Liam's well-being when his leg was broken and approaching Taylor to see if she was alright. Amelia can get very emotional when pushed. After spending over 7 months in The Plane, her attitude begins to change, likely due to the long period of time she spends in The Plane. She became more irritable and likely to snap at people. She avoids questions and seems to now be uncertain if she really wants to go home. Possibly, she’s been in The Plane for so long that the thought of most things back in her world now seem alien to her, even almost forgetting her real name. Once she was bought back to Earth, she heavily struggled to get used to it again due to how long she was on The Plane. She also struggles to accept Airy's apology.

Charlotte Stern typically comes off as grouchy and violent when pushed. She's also quite competitive, going out of her way to win each challenge. She fiercely believes in her own independence and self-sustainability, to the point where it becomes problematic. This is likely the cause of her rashness and cynicism, examples being disregarding safety hazards even if they could end with her getting injured, and accusing her friends of only giving her cash to raise themselves up as heroes, even spending the money they gave her on expensive electronics just to prove her point, and also because she couldn't control her spending impulses. This is also more subtly shown in the fact that she single-handedly does most of the challenges in The Plane. After a long time on the Plane, she suddenly becomes much more tame and uneasy. She realizes the abnormality of the show, along with completely turning her values around and letting her become more self-aware. She doubts if there really is a prize and questions the remaining contestants about various things. Now that she's back on Earth and got her mold treatment, she still finds it quite hard to relax sometimes.

Taylor Nolan is a teenager. Due to that, she acts slightly more immature than most other contestants. She is friendly and talkative, and was initially eager to participate in ONE, unlike the other former contestants. She tends to get in arguments over small things, seldom to the annoyance of other contestants such as Charlotte. Taylor happily socializes with her friends, but she also is easily worried.

Charlie Howling is a literal baby, therefore doesn't really understand his surroundings. He goes around with a carefree spirit, always holding a smile or just sleeping.

Airy keeps a bored, deadpan attitude most of the time, and seems to lack in empathy. Airy is shown to be a very apathetic and detached person, disconnected and jaded after years of solitude in his world. When he died, he spent an unspecified amount of time in The Waiting Room trying the radio until he came to the world he now resides in. After accidentally figuring out how to teleport people from other worlds into a planet he calls The Plane, the best explanation he could come up to soothe the scared people with was that they were in a gameshow, and they would compete for a prize. He likely did not have any malicious intention in hosting his show, and simply viewed it as a source of entertainment in his loneliness. He is only seen smiling when interacting with all these people he once tormented so, and is slowly adjusting to the real world again. Also clingy and very, very touch starved.