|Spoiler Alert: This article or section contains details about plotlines not covered in the anime. Do not proceed unless you wish to be spoiled. |
The Day After (ザ・デイ・アフター, Za Dei Afutā?) is a bonus side story, written by Kawahara Reki, that was included in the limited edition version of volume 9 of the DVD/BD sets for the anime. The story is about a strange phenomenon that had been occurring to Asuna in ALfheim Online.
On June 21, 2025, Kirito and Asuna were doing homework together inside an inn in Yggdrasil City. They started talking about a problem Asuna was having: sometimes she felt that she was separated from her avatar and lost control for a moment. After discussing the different possibilities, they decided to ask Yui for help. When she logged out, Asuna saw a scene outside her window, which brought back memories that were not hers.
The next day they talked to Yui, and, although she was unable to identify the problem, she speculated that it must be a player's registered information that was interfering with Asuna's gameplay. They had to end their discussion there because it was time to meet the others because they were going to face New Aincrad's 8th Floor boss, Wadjet the Flaming Serpent.
During the fight, Asuna lost control once again, but was saved by Kirito, who had been warned by Yui about the phenomenon happening again. After an hour of battle, the raid party was wiped and everyone returned to the Labyrinth's entrance. Although the others wanted to try again, Kirito decided to leave and was followed by Asuna and Yui.
Asuna followed Kirito until he stopped outside the 27th Floor. They sat on an edge of Aincrad, where he shared his belief that the one trying to make contact with her was Sachi, a member from his former guild. When Kirito wondered why Sachi would be trying to contact Asuna instead of him, Yui explained that Kirito was using an avatar different from his avatar in Sword Art Online, but Asuna's avatar had a hidden "married" status with it. At that moment, Kirito declared that three minutes later would be exactly two years since the time Sachi died. As soon as that time passed, Asuna had the strongest feeling of detachment and had a vision, in which Sachi requested her to tell Kirito that she was happy.
The next day, the Clearers prepared to face Wadjet the Flaming Serpent again. With ten minutes remaining, Yui convinced Kirito to change his hair style, since she wanted to feel more comfortable while sitting on his head.