Ep 22. E 22

Kirito investigates the Death Gun by going into Gun Gale Online himself, while Sinon continues to play in the tournament to gather information. Kirito discovers that Death Gun's true identity is a former member of Laughing Coffin, a guild of players that committed murder and caused chaos in the original SAO game.

Meanwhile, Sinon faces off against the sniper who had previously shot her, and manages to defeat him with the use of a new weapon. She then faces the final opponent in the tournament, a player known as "Absolute Sword," who is revealed to be Zekken, a mysterious and powerful swordsman who has been challenging other players to duels.

Kirito and Sinon reunite and discover that Zekken is actually a girl named Yuuki, who reveals that she is suffering from a terminal illness and has been using the virtual world as an escape. She invites Kirito to join her "guild," the Sleeping Knights, and help them defeat a powerful boss monster known as the "Floor Guardian."

Kirito agrees to help, and they embark on the quest to defeat the Floor Guardian. Along the way, Yuuki opens up to Kirito and reveals more about her past and her illness, while also showing off her incredible sword skills. The Sleeping Knights manage to defeat the Floor Guardian, but at a great cost.

As the group prepares to disband, Yuuki reveals that she wants to spend what little time she has left with her new friends. Kirito offers to help them create a new memory by taking them to Aincrad, the first game they all played, and reminiscing about the past with them.

In the end, the Sleeping Knights disband and Kirito returns to the real world, reflecting on the impact that the virtual world can have on a person's life. The episode ends with Kirito receiving a message from Asuna, setting up the final episode of the season.