Gi Guk-seo

Seong Gi-hun (Korean: 성기훈; [sʌŋ.ɡi.βun] ), also known as Player 456, is a fictional character and the main protagonist of the South Korean dystopian survival thriller television series Squid Game, made for Netflix. He was created by series creator Hwang Dong-hyuk and portrayed by Lee Jung-jae, who was cast out of a desire to affect his reputation as a cool actor and show the humanity behind his role. Gi-hun took multiple aspects from Hwang's life, including his neighborhood, his childhood friend's name, aspects of his uncle, and his own struggles with gambling and failure. When designing his character for season 2, Hwang aimed to make him a Don Quixote–like character, revolting recklessly against the system. Lee found him to be the most "heartbreaking" character he has portrayed. He is voiced in the English dub by Greg Chun.
Gi-hun was a divorced former chauffeur and gambling addict who joined in a secret life-or-death contest consisting of six children's games where he competes with 455 other players for a cash prize of up to 45.6 billion won after incurring significant debts from gambling and unemployment. During participation, he makes allies with various other participants, including Ali Abdul, Cho Sang-woo, Kang Sae-byeok and Oh Il-nam whilst making enemies with Jang Deok-su, Byeong-gi, The Recruiter and indirectly with Hwang In-ho. Following his regretful victory in season 1, he returned as a participant in the games of the second and third in an attempt to end them. He makes allies with various other participants, including Kang Dae-ho, Park Jung-bae, Park Yong-sik, Cho Hyun-ju, Jang Geum-ja, Kim Jun-hee, Park Gyeong-seok and Hwang In-ho whilst making enemies with Im Jeong-dae, Thanos, Seon-nyeo, Kim Yeong-sam, and briefly with the Masked Officer and Kang No-eul.
Gi-hun was well received as a character in season 1, with Lee winning multiple awards for his performance, including a Screen Actors Guild Award and an Emmy. Critics discussed the parallels between his life and real-world problems in South Korea, including the 1997 Asian financial crisis. His season 2 and 3 portrayals were more mixed, with critics feeling his character's actions were frustrating and made little sense. Despite these criticisms, Lee has been praised for his ability to shift from a lighthearted character to a darker one in the second and third seasons.

Biography fallback source: Wikipedia