Player 001 is the most important competitor in 'Squid Game' seasons 1 and 2. What to know about the latest character to wear the number.

• Player 001 is a main character in seasons one and two of "Squid Game."
• The number was bestowed on Oh Il-nam, a dying old man, in season one.
• Here's what to know about the new Player 001, Oh Young-il.

Warning: Spoilers ahead for "Squid Game" seasons one and two.

In season two of Netflix's hit series "Squid Game," lead character Seong Gi-hun is betrayed again by Player 001.

The first season became streamer's most-watched show of all time and helped spark global interest in Korean dramas. One of the main characters, Oh Il-nam (O Yeong-su), is an old, dying man who entered the competition of deadly children's games to relive his childhood.

He is given the "Player 001" jumpsuit and becomes allies with Gi-hun (Lee Jung-jae) and his friends before Il-nam is killed during the marbles game in episode six.

However, a year after Gi-hun wins the games, Il-nam reveals to him that he faked his death and was the creator of the games, posing as a player.

Before Il-nam dies of natural causes, he tells Gi-hun that he designed the games to amuse other wealthy people and test people's morals.

This inspires Gi-hun to shut down the games for good, and he agrees to enter the competition again in season two to complete this plan.

This time, he meets another Player 001, who wants to become his ally.

Player 001 is the Frontman without his disguise.

Season two's Player 001 tells his fellow survivors that his name is Oh Young-il, but he is really Hwang In-ho, the Frontman.

In-ho is played by Lee Byung-hun, a South Korean actor who has also starred in American action films including "G.I. Joe: The Rise of Cobra," "Red 2," and "Terminator Genisys."

In season one, In-ho led the competition from the command center and ensured it ran smoothly; however, for most of the season, he wore a black mask and raincoat, hiding his identity.

In-ho had spoken to Gi-hun before, but he was masked and using a voice changer. So Gi-hun doesn't recognize In-ho's voice in season two while pretending to be Young-il, so is never suspicious of him.

It is unclear what In-ho's plan is, but in season two, he infiltrates Gi-hun's group, tries to subtly talk him into supporting the games, and sabotages the players' rebellion in the season finale.

In the finale, In-ho also fakes his death, reapplies his mask as the Frontman, and kills Gi-hun's close friend right in front of him.

The Frontman is the brother of former detective, Hwang Jun-ho.

In season one, a detective, Hwang Jun-ho (Wi Ha-joon), infiltrates the competition as a guard in search of his missing brother, In-ho. He discovers that his brother won the competition five years ago and now runs it as the Frontman.

But Jun-ho is shot by In-ho during his escape. Jun-ho survives but loses all the evidence of the games to give to the police.

In season two, Jun-ho joins Gi-hun's team in tracking down the organization running the competition, but hides that his brother is in charge.

The Frontman enters the games to save his wife, but she dies.

While posing as Young-il, In-ho tells Gi-hun that he is competing in the games to get enough money to help his sick, pregnant wife. He says he was fired from his job after borrowing money from a vendor because his bosses thought it was a bribe.

This may be the one time In-ho tells the truth to Gi-hun.

In episode two, Jun-ho visits the grave of In-ho's wife to check for signs he has visited recently. Later, Jun-ho and his mother speak about how they couldn't afford to help In-ho save his sick wife. Jun-ho says In-ho decided to take a bribe, so they shouldn't blame themselves for her death.

If this is true, and In-ho did initially compete in the games to save his wife, perhaps he was too late to save her after winning. His story could be mirroring Gi-hun's, who competes in the games in season one to pay the medical bills for his mother, who dies before he returns.