Nao Kanzaki is the female lead and protagonist of Liar Game. She is introduced as a college freshman who is exceptionally good-natured and trusting, to the point that she has earned the nickname Naive Nao. Her life takes a dramatic turn when she receives a package containing one hundred million yen and a card informing her that she has been chosen to participate in the Liar Game Tournament. This is a high-stakes competition in which contestants are encouraged to deceive and steal from one another, with losers incurring debts proportional to their losses. Nao initially tries to seek help from the police and a lawyer, but neither can assist because no crime has technically been committed. She is eventually directed to a former genius con artist named Shinichi Akiyama, who has just been released from prison.

Despite her naive nature, Nao is naturally expressive, cheerful, strong-willed, and full of energy. She often ends up in tears when deceived, but she possesses a surprising amount of courage and initiative. Her core belief is that the Liar Game is ultimately about how honestly a person can remain, and she insists on playing with trust, empathy, and a desire to help everyone, including her opponents. This makes her a direct challenge to the game's premise of deceit and manipulation. She is not unintelligent; rather, she chooses not to play by the same rules as others. Her emotional intelligence and unwavering integrity allow her to earn the trust of contestants and, over time, to develop the ability to read people, spot inconsistencies, and use her honest reputation as a strategic tool. She becomes a late-game intelligence type whose strengths, such as creating emotional pressure and fostering cooperation, become increasingly valuable as the games progress.

Nao's motivation is deeply rooted in her compassion. She is always concerned about her teammates and opponents alike and tries to save them from debt, often at the cost of sacrificing herself by remaining in the game or paying off others' debts. Her father is in the hospital, and she is determined to protect him from worry. She initially enters the game only to escape, but later chooses to return willingly, alongside Akiyama, with the goal of releasing all participants from the tournament and exposing the organization behind it.

Her key relationship is with Shinichi Akiyama, who becomes her partner and protector. Akiyama is a psychological genius who designs intricate strategies to defeat opponents, but he relies on Nao's moral compass and her ability to influence players on an emotional level. Their partnership is complementary: Akiyama handles the logical and tactical aspects, while Nao provides the human connection that can break the cycle of distrust. She also forms relationships with various opponents throughout the tournament, often trying to reform them or help them escape debt.

Throughout the story, Nao undergoes significant development. She begins as a naive and often helpless participant, but she matures into a more perceptive and capable player. She learns to read people, to use her honesty strategically, and to subtly manipulate situations by leveraging her reputation. Her growth is gradual, and by later arcs, she stabilizes situations that even Akiyama finds difficult to handle. She becomes a player who rewrites the rules of the game by introducing trust as a powerful currency, undermining the dominance of purely logical or manipulative players like Yokoya Norihiko.

Her notable abilities are not traditional intellectual prowess but rather exceptional emotional intelligence, empathy, and an unshakable moral core. She can create emotional pressure where logical traps fail, and her genuine desire to help others often disarms opponents and encourages cooperation. She has a talent for restoring agency to other players and breaking the influence of ruthless adversaries. Her presence forces the game's structure to crack, as she proves that being the only honest person in a room full of liars can be the strongest move of all.