Sean MacGuire

MacGuire is said to be a cheerful man who enjoys spending his time telling stories at the gang's campfires, particularly about his family history. He loves being a part of the action, but he is relatively inexperienced and often overestimates his own abilities. At Clemens Point, he playfully tries to poke fun at Arthur, calling him 'English' and 'King Arthur'. He is perhaps the most talkative member of the gang, as Charles remarks that he speaks incessantly,[4] and Arthur is mildly aggravated by his constant teasing at times. However, he is also somewhat lazy, literally falling asleep during guard duty multiple times, drawing the ire of Hosea.[5]

Sean appears to have a positive relationship with Lenny, who once tried to teach Sean (who is illiterate) how to read.[6] The two are often seen conversing, and Lenny tells Arthur at one point that he likes Sean. By contrast, Sean often expresses his dislike of Micah.

Sean and Karen have a flirtatious relationship. Although Karen says she "hates [Sean]" and that he only loves her when they're drunk, Sean remains convinced that she loves him, and the two have sex after Sean is first rescued. During the act, Karen can be heard crying and saying she just wants someone to "see her", to which Sean says he does. However, Sean's true feelings about her are unknown, as he could have simply said that to continue the moment in a typical act of bravado, and are not expanded upon as he dies shortly after. Nevertheless, his death has a major impact on Karen, who becomes more and more of a disheveled alcoholic as the game progresses, reacts irritably to everyone as the gang disintegrates around her, and ultimately disappears from the public eye, with Tilly believing she drank herself to death.

Sean has a generic, very much stereotypical Irish accent. Unlike Molly O'Shea, who has a distinct Dublin accent, MacGuire's is harder to pinpoint. The actor, Michael Mellamphy, is a Cork native but MacGuire has no distinct Cork accent.