One of the coolest things about Sword Art Online: Alicization – War of Underworld has been it’s additions to the story found in the original novels–most notably those coming from the feature film Sword Art Online: Ordinal Scale. Episode 17 of War of Underworld features the most prominent of these with the return of Ordinal Scale’s villain-idol combo of Eiji and Yuna. Yet, why they are there to help Kirito’s gang is never explained–well, not in the anime anyway.
Image source: アニプレックス on YouTube
When we last saw Eiji in the Ordinal Scale film, he had been defeated by Kirito and had his memories of SAO and the original Yuuna wiped by Yuuna’s father, Tetsuhiro Shigemura (in his attempt to build an AI of his dead daughter using the memories of those who encountered her in Sword Art Online.) However, with the defeat of the 100th floor boss in Sword Art Online, he stumbles into the arena dazed at the return of his SAO memories, hearing Yuuna’s voice telling him that he remembered her dream.
As for Yuna, it’s a bit more complicated–mainly because there are two of her. “Black Yuna”–i.e., the black-clad virtual idol by Eiji’s side for the majority of the film, is an AI built on the SAO framework (like Yui) that is the personification of the original Yuuna’s dream to sing in front of a large audience. With the face and voice of the original, it is her job to evoke memories of Yuuna in the minds of SAO survivors.
Image source: アニメ ソードアート・オンライン 公式 on Twitter
While she is turned off by Professor Shigemura when he starts the final step of resurrecting his daughter, Black Yuna is seen once again in the film’s closing moments performing a small outdoor concert on TV.
“White Yuna”–i.e., the AI designed to resurrect the original Yuna through the memories of SAO survivors and machine learning–is built out of the code of SAO’s 100th-floor boss. With the destruction of said boss at the climax of the film, her program begins breaking down and she disappears, returning all the SAO players’ stolen memories.
Image source: アニプレックス on YouTube
When Eiji and Yuna arrive to fight PoH in War of Underworld they appear as ALfheim Online characters–with Eiji a fairy and Yuna a pixy navigator. However, like Yui, Yuna appears to be able to change into her original programmed shape–i.e., Black Yuna–at will and does so for their battle. But over the course of the fight, both Eiji and Yuna revert to their Sword Art Online forms–with Yuna even referring to Eiji as “Ei-kun” like the original Yuuna did.
While it’s an amazingly cool fight scene with awesome music alongside it, it does raise some major questions. How is Yuna, a famous pop-singer AI, still in the hands of Eiji, a known criminal? How does she seemingly have the memories of the original? And perhaps, most importantly, why would Eiji ever want to help Kirito and the gang–i.e., the people who prevented the resurrection of his one true love, Yuuna?
The answers to the questions and more are found in the novela Sword Art Online: Cordial Chords.
Cordial Chords was included in the Japanese Limited Edition Blu-Ray/DVD release of Ordinal Scale. Set three days after the end of the film, it follows Kirito as he gets a mysterious call for help from a newly released Yuna desktop avatar. Over the course of the novela, Kirito reunites with Eiji, who is released from police custody when Klein and his guildmates refuse to press charges. Together they sneak into the server room containing the original SAO server and log in. There, at the place where Yuuna died, they find Black Yuna in a horrible state with her programming breaking apart.
With Professor Shigemura stepping down from his role within the company, the new “owners” of Black Yuna set out to better exploit her. Thus, they made 5 copies of her to be able to do more with her. However, the structure of SAO’s AI programming does not allow for copies to exist–each AI is designed to be unique. Because of this, all the copies along with the original are currently breaking down–with the copies likely already gone by the time Kirito and Eiji find Black Yuna.
However, Yui explains to the pair that the reason Black Yuna is still in existence at all is due to the remnants of White Yuna trying to repair the damage using her own rapidly disappearing code. However, to complete the repairs, Black Yuna must receive data that symbolizes her most precious memory. But while Black Yuna was designed only to care about singing, Eiji realizes that what she cared about more was being with him–working together to collect the “candy” in the jar she always held. So he gives her the original candy jar Black Yuna’s was based on–the virtual item that the real Yuuna gave Eiji at the moment of her death.
Using this and her remaining code, White Yuna merges with Black Yuna to create a new person–mostly Black Yuna but with some of the memories of White Yuna. So while this new Yuna is not exactly the girl he loved reborn, she is the closest thing.
With this in mind, it makes perfect sense for Eiji to come to Kirito’s aid. While they may not be friends exactly, the reason this new Yuna and Eiji are together is in large part due to his help.
Image source: アニメ ソードアート・オンライン 公式 on Twitter
If you’re interested in more of the lore behind what happens in episode 17 of War of Underworld, I recommend you read Sword Art Online creator Reki Kawahara’s comments on the episode (translated here by Dreadful Decoding). He explains other seeming plot holes like how Yuna can connect so easily to Underworld while Yui can’t (Yuna is transferring over using the deceased Yuuna’s SAO account) and how Eiji and Yuna can use Incarnation while not being connected via STL (the two are connecting via the original SAO server and there’s still some unexplained things about the old girl). It’s a fantastic read so be sure to check it out!
Sword Art Online: Alicization – War of Underworld can be viewed on Crunchyroll, Funimation, HIDIVE, Hulu, Muse Asia (Asia), AnimeLab (AU/NZ), Wakanim (EU)
Top image source: アニメ ソードアート・オンライン 公式 on Twitter.
This was a wonderful article. It explained everything I was looking for about Eiji and Yuna perfectly. I love SAO and I was in the middle of watching “Episode 17” when I stopped to search for a good article to help me understand why they had showed up looking the way they did. Thank you!