• Aliases: Player 124, Nam-su
• Born: 1997, Age 27
• Gender: Male
• Portrayed by: Roh Jae-won
• Occupation: Club Promoter at Club Pentagon
• Affiliation: Club Pentagon, 37th Squid Game, Team Thanos
• Relationships: Thanos, Se-mi, Min-su, Gyeong-su, Myung-gi
• Status: Pushing painted daises

Before the games, Nam-gyu worked as a club promoter at Club Pentagon, where he became acquainted with the rapper Thanos. He regularly brought him drugs and got him free drinks through his position at the club. He was an active drug user as well, having tried nearly every street drug he could obtain through the clubbing scene.

In 2024, Nam-gyu invested large amounts of money in a cryptocurrency called Dalmatian, on the advice of the YouTube channel MG Coin. Unfortunately, the currency turned out to be a scam, and Nam-gyu lost over 300 million won when the rug was pulled. This led him to participate in the Squid Games.

Throughout the Games, he forms a relationship with Thanos. Thanos seeks revenge on Myung-gi (MG Coin), the crypto influencer whose greed caused him a huge financial loss. Together they plan to take down Myung-gi, whom they blame for their respective downfalls. Their alliance is not only based on a desire for vengeance but also on the desperation they both feel after losing everything in their lives.

Nam-gyu is shown to be a more violent, cruel and sadistic person, more than even Thanos is. While Thanos treats his teammates with respect and is even upset by Gyeong-su's death , Nam-gyu bullies both Se-mi and Min-su frequently, to the point where even Thanos calls him out for it, and where he kills Se-mi.

While not nearly as unhinged as Thanos, Nam-gyu is still somewhat mentally disturbed. Unlike Thanos, he doesn’t care about using other people to his advantage and sees them as disposable. He also shares Thanos' vengeful nature, and sees any comrade who opposes him as a traitor. He can also act very rudely towards others people and displays crude and inappropriate behavior.

He feels some resentment towards Thanos' treatment of him, feeling as though he was inferior to him. Following his death, he curses Thanos for believing he was an idiot, and takes his cross necklace, taking Thanos' place as the main spokesperson of the group.

In line with his reckless behavior, Nam-gyu states that he believes an individual can escape the fear of death by telling themselves they don't care about whether they live or die.

However, he also appeared to be a coward as he heavily relied on taking the pills to suppress his fears in the games after he asked the guards where he left his necklace in Hide and Seek so he can retrieve it and begged Min-su after knowing he took the drug necklace only for him to throw the cross at the Jump Rope platform.

Nam-gyu is shown to have extreme anxiety, shown through his shaking hands and ability to rely on the pills to gain confidence. More evident showings of his anxiety is his trembling nature whenever his reliance is challenged.

When Nam-gyu gets nervous, his legs shake a lot, this was seen in both the Six-Legged Pentathlon and Jump Rope.

Nam-gyu is touchy with other players, particularly Thanos and people he's familiar with.

• Namgyu ranked 24th place in the Games.
• A club similarly-named to Club Pentagon, "Club Octagon", exists in Seoul.
• Nam-gyu shows up physically in the most episodes of any Team Thanos member.
• As an O player, he took the longest to change his vote to X.
• Nam-gyu has a total of 7 tattoos on both arms.
• During The Starry Night, Nam-gyu starts singing the real-life song "Love Scenario" (Sarang-eul haetda), by the South Korean boy band group iKon.