Wade Watts, whose avatar is named Parzival, is driven to the quest by a desire to escape the limitations and meaninglessness of his life, which is marked by a lack of close relationships. Wade is an orphan; at the beginning of the novel, he lives in the stacks—a poor, crime-ridden area—with his resentful aunt. He has one friend in real life and one friend inside the OASIS. At first, Wade's virtual life inside the OASIS is more vivid to him than his real life, but then he becomes inspired to pursue a romantic relationship with Art3mis, and during the quest, he starts to care more about the relationships he develops than his own success. When he wins, he loses interest in the virtual reality that previously consumed him. As a result of his virtual quest, he develops the courage to live life.
Art3mis, whose real-life name is Samantha Evelyn Cook, took her avatar name from the Greek goddess of the hunt. Art3mis runs a popular blog about her efforts in the quest and is an obsessive, knowledgeable, and highly skilled gunter on par with Wade. She is the second to find the Copper Key and the first to find the Jade Key. She views Wade as a rival in the competition and at times seems offended when his success outpaces her own. In real life, she is a focused and idealistic young woman living in British Columbia. She wants to use the prize money to end world hunger and fix the energy crisis. She struggles with feeling unattractive, especially because of a large birthmark covering half her face. Before Wade meets her in the Tomb of Horrors, he has a "massive cyber-crush" on her. She responds to Wade's romantic advances guardedly because she views them as a distraction from the quest. However, she provides crucial help for Wade as he clears the Third Gate. She dates him as soon as the quest is over.
Aech (pronounced like the letter H), whose real-life name is Helen Harris, becomes close friends with Wade online through their shared quest for Halliday's egg as well as other common interests, such as music and movies. Because her avatar is a Caucasian male, Wade thinks of her as such, and he is startled when he finally meets the real-life Aech—an African American young woman.
Daito, whose real-life name is Toshiro Yoshiaki, is the fourth gunter to find the Copper Key and clear the First Gate. He is a video game prodigy with a love of samurai movies. When he meets the other gunters in Aech's chat room, he introduces Shoto as his little brother. The two have never met in real life, but they operate as a team in the quest. Daito is an emotional person, and his anger is easily triggered when he feels his privacy and independence are threatened. He flies into a rage and temporarily severs his relationship with Shoto when Shoto suggests they meet in real life. He is enraged by the Sixers' tactics, which violate his core principle of honor. When Wade urges Daito and Shoto to take the Beta Capsule, their prize from a minor quest they completed as a team, Daito is impressed and calls Wade "a man of honor." He is assassinated by IOI in real life while he is logged into the OASIS and on the verge of obtaining the Jade Key. His success in the quest makes him a national hero in Japan; prior to the quest, he had been a hikikomori, a young person who withdraws into total isolation inside the family home.
Shoto, whose real name is Akihide Karatsu, is bilingual in English and Japanese and well-versed in American pop culture. Much younger than his partner Daito, Shoto also loves samurai movies and was a hikikomori, a young person choosing a life of isolation in their family's home, prior to the quest. He is the fifth gunter to find the Copper Key and clear the First Gate. He is much more open and emotionally generous than Daito and expresses regret after Daito's death that Daito refused to meet him in real life. After Daito's death, his primary goal is to avenge Daito's murder rather than find the egg. He gives the Beta Capsule to Wade Watts, in accordance with Daito's wishes, and accepts the gift of a samurai sword from Wade. Nolan Sorrento kills his avatar when Shoto attacks him kamikaze-style during the battle for Castle Anorak.
Ogden Morrow met James Halliday in junior high school, and the two bonded over Dungeons & Dragons. Morrow is sociable and easygoing, with a mind for marketing and business. He convinces Halliday to mass-produce his first game, Anorak's Quest, which launches their company. He helps develop the OASIS, but after it is released, he retires and lives a life of rural seclusion with his wife, Kira Underwood. He considers the OASIS "a self-imposed prison for humanity." He has a falling-out with Halliday some years before Halliday's death and rarely makes public appearances either in real life or in the OASIS. He is outspoken in his criticism of the media and IOI. He watches Wade and the other gunters as they compete, and eventually he offers them help. He intercedes in the quest because he sees the Sixers as a threat to the competition's intended spirit and he is determined to stop them from winning.
Nolan Sorrento has a Ph.D. in computer science and was a high-profile game designer before becoming the Head of Operations at IOI. Wade calls him "a decent coder, back before he sold his soul." As leader of the Sixers, he sends e-mail bombs to Wade and the other successful gunters after they find the Copper Key, hoping to either recruit them or kill them. Only Wade responds to his request for a meeting. Sorrento is a ruthless man, determined to win the contest at any cost; if he does, IOI can control and monetize the OASIS. Despite the Sixers' significant financial and practical advantages, they lag behind the independent gunters at the quest's start. When Wade refuses to cooperate, Sorrento has the Sixers detonate explosives around Wade's home, killing dozens of innocent people. He has Daito killed and also tries to kill Art3mis and Shoto. Sorrento challenges the independent gunters to a battle at Castle Anorak, confident he will win. Shoto is killed, but Wade then kills Sorrento's avatar. Afterward, Sorrento orders his mercenaries to detonate the Cataclyst, which vaporizes everything in sight.