Sang-woo uses Ali’s trust in him to his advantage. After losing to Ali fair and square, Sang-woo convinces him that there will be another round of the game, and that they have to split up to see how the other teams are doing to see who they could be up against. Sang-woo offers to make Ali a safer pouch to hold his marbles, and Ali trusts him, handing over his pouch. It isn’t until the game is over that we realize that Sang-woo switched out Ali’s marbles for rocks, approaching one of the masked guards and claiming the victory for himself. Ali calls out for Sang-woo, looking for his friend as the game comes to a close.
Player 218 Cho Sang-woo and Player 067 Kang Sae-byeok
This season 1 betrayal isn’t quite as surprising given Sang-woo’s manipulation of Ali, but that doesn’t make it any less heartbreaking. Right before the final game, Sang-woo, Seong Gi-hun (Lee Jung-jae), and Kang Sae-byeok (Jung Ho-yeon) are given a fancy steak dinner by their wealthy overlords (and of course allowed to take their steak knives with them). Kang Sae-byeok is doing her best to hide a stab wound inflicted by the explosion of the glass bridge in the previous game, but that doesn’t stop Sang-woo from killing her in the players’ quarters anyway to get rid of his competition before the final game.
Player 456 Seong Gi-hun and Player 001 Oh Il-nam
Seong Gi-hun and Oh Il-nam become unlikely allies throughout season 1’s games. They do their best to help each other survive up until the fourth game. Like Sang-woo and Ali, Gi-hun and Il-nam end up as partners, testing the limits of their friendship. Il-nam appears to struggle greatly with his dementia in this challenge, leaving Gi-hun to decide whether or not to use that to his advantage to win the game. In the end, he does, somewhat, and Il-nam is aware enough to know that he did. But still, he refers to the two of them as gganbu, trusted friends, and seems to accept his death graciously. This is where the real betrayal comes in.
In the season finale, Gi-hun receives a mysterious invitation from Il-nam a year after winning the games. It turns out that not only did his former friend not get killed in the games like he thought, but he’s also the one who created the games in the first place. Sure Il-nam actually does die a few moments later, but that doesn’t make this betrayal hurt any less, for us or Gi-hun.
Hwang Jun-ho and Hwang In-ho
Hwang Jun-ho’s (Wi Ha-joon) search for his missing brother is one of the best subplots in season 1. Through Jun-ho’s search, we get to learn more about how the games work behind the scenes, the rich scumbags who find enjoyment in them, and the identity of The Front Man – a mysterious masked figure pulling the strings. After Jun-ho tries to escape the island and finds himself cornered, The Front Man takes off his mask and reveals himself to be Jun-ho’s missing brother Hwang In-ho (Lee Byung-hun). In-ho was a contestant in one of the previous games and won. After his victory, he was offered the job as The Front Man. In-ho tries to recruit his brother, but when Jun-ho refuses, he shoots him in the shoulder, sending him tumbling off the side of a cliff into the waters below. It’s a heartbreaking moment that shows us just how cold and calculating In-ho can be.
Player 456 Seong Gi-hun and Player 001 Oh Young-il a.k.a. The Front Man
Speaking of Hwang In-ho, his betrayal of Gi-hun and the others really shouldn’t have been a surprise. From the moment we saw him step out in the 001 player uniform under the identity of Oh Young-il, it was never really a matter of if he would betray Gi-hun, but rather when. But even though we saw this betrayal at the end of season 2 coming a mile away, that doesn’t make it hurt any less.