Kirito and Heathcliff arrange to duel in a coliseum on the 75th floor. Asuna is displeased with Kirito for accepting Heathcliff's challenge, since he has a unique skill like Kirito's Dual Blades, "Holy Sword", which grants him peerless attack and defense power, such that his HP bar is never seen dropping low enough to turn yellow. Kirito understands the risk, but still plans to win.
Kirito makes his way into the packed coliseum for his duel with Heathcliff: a first-blow battle, with the winner being whoever manages to deplete a set portion of the opponent's HP. The two seem evenly matched, with Kirito's dual-wielding swords and speed balancing out Heathcliff's attack and tanky defense. Just as it seems Kirito is about to land the winning blow, however, Heathcliff suddenly dodges his attack with unusual speed and counters, defeating Kirito. With this, Kirito is officially conscripted into KoB.
The following day, as Kirito prepares for his duties with KoB, he explains to Asuna about the Moonlit Black Cats, and how their demise is the reason why he avoids joining guilds. Realizing his grief, Asuna comforts him and promises to protect him.
Kirito's first duty with KoB is a training exercise with Godfree, a senior member of the guild, and Kuradeel, who apologizes for his previous actions and promises to be a good guildmate.
While taking a break during their excursion, however, Kirito and Godfrey are rendered paralyzed by their poison-laced drinks. Kuradeel then proceeds to murder Godfree, and reveals to Kirito that after their duel, he joined the PK guild Laughing Coffin.
Before Kuradeel can kill Kirito, however, he is attacked by Asuna, who came when she saw Godfree's player indicator vanish from her map. Kuradeel begs for mercy and takes advantage of Asuna's lenience to try and attack her, but Kirito fends him off and drives his hand into his gut, depleting Kuradeel's HP and killing him.
Asuna breaks down into tears, believing she was the reason Kirito almost died and begging him to forget about her. Kirito, however, suddenly kisses her and comforts her. He asks Asuna to let him stay with her that night. At her house after dinner, Asuna dims the lights in her house and unequips her clothing, undressing herself until she was only in her underwear. When Kirito realizes what Asuna wants, he becomes embarrassed, not realizing what he meant when he asked to stay the night with her, much to Asuna's annoyance.
That night in bed, Asuna decides to take a break from the front lines, believing that something bad could happen if she kept fighting for the time being. Kirito tells her that the 22nd floor had a village where they could stay, and proposes marriage to her. Asuna tearfully accepts his proposal.