Asuna Yuuki, more commonly known by her online handle "Asuna," is the in-game wife and real-world girlfriend of Sword Art Online's protagonist, Kirito. While she began her role on the show as a powerful lead character who fought alongside Kirito every step of the way while trying to escape the virtual world of Aincrad, her role in the series has not always been so prominent. However, despite the show's continued sidelining of her character, the bold and loyal caramel-haired swordswoman has still remained a fan favorite over the show's four seasons.
Introduced in the first arc, Asuna was one of the original players trapped in the virtual world of Sword Art Online. She was one of Kirito's first friends in the game as the two of them formed a party together after being left out by the other players. Throughout the Aincrad Arc, Asuna occupied the spot of the co-lead alongside Kirito, playing a role in every major facet of the initial 14-episode arc.
Though the first few episodes of the Aincrad Arc focused predominantly on Kirito, as the black-haired protagonist progressed through the game, Asuna's role in his life — and therefore, in the show — grew too. And as she became one of Kirito's favorite people in Aincrad, fans began to fall in love with her too. For fans, Asuna became a beautiful, model young woman who was a natural leader, personable, could hold her own in battle and even knew how to cook an exceptional meal -- the perfect isekai waifu. As Kirito began to fall in love with her, it became easy to understand why he had fallen so hard for the auburn-haired beauty.
But beyond her many appealing qualities, Asuna was a perfect foil and motivator for Kirito within that first season. While Kirito was angsty and preferred to be alone, Asuna was cheerful and eager to help others. Because of their differences, the two were able to mature and grow in a relationship together; even going as far as becoming in-game parents. Plus, if it wasn't for Asuna -- and her incredibly selfless sacrifice when fighting Heathcliff -- Kirito might never have beat the game. Kirito and Asuna's relationship seemed absolutely perfect as if nothing or no one could come between them because they were so clearly meant for each other.
The first arc of Sword Art Online set Asuna up perfectly to be Kirito's leading lady, someone who viewers could watch mature and grow in the show's coming seasons, as well as one-half of a power couple fans could root for as the show continued.
However, beginning with Episode 15 and the start of the Fairy Dance Arc, Asuna's character was reduced to a background role in favor of replacing her co-lead spot with Kirito's younger sister Suguha, aka "Leafa." This background relegation continued into Season 2 with the beginning of the Phantom Bullet Arc, which introduced another new character, Shino "Sinon" Asada, as Kirito's new leading lady. Even in last year's Season 3, Asuna only played a peripheral role, as new character Eugeo became Kirito's co-lead.
All the expectations the show laid out for Asuna in the show's first arc were completely demolished. The brave, fearless, swordswoman who had impressed Kirito so much in Episode 2 suddenly had become just another member of Kirito's ever-growing harem. And while Asuna remained loyal to her in-game husband, Kirito's list of lady friends only continued to grow in the show's coming seasons. Even in the original movie, Sword Art Online The Movie: Ordinal Scale, which wasn't based on the source light novels, Asuna was reduced to a weakened state while Kirito stood strong in the spotlight.
As seasons progressed, it became disappointing, frustrating and even insulting for fans watch a strong female character they had so quickly fallen in love with becoming relegated to nothing more than a pretty plot device.
But the empowered young girl fans loved in the Aincrad Arc is still there somewhere, though the show hasn't made her the easiest to find.
The Mother's Rosario Arc of Season 2 gave Asuna a small, but important, moment to shine as she became the arc's leading protagonist in lieu of Kirito. Even though Mother's Rosario was on the shorter side with only seven episodes, it's still regarded as one of the best-received arcs of the anime. Additionally, in the latest season of the show, Sword Art Online: Alicization – War of Underworld, Asuna resumed her role as leading lady and Kirito's primary love interest when she journeys to the Underworld to save her comatose boyfriend. With Kirito in a vegetative state for the majority of the season, Asuna was finally given another moment to properly remind audiences why they liked her so much in the first place.
Clearly, Asuna is still a well-written character who has become a fan favorite for many viewers. While it's unfortunate that the writers have continuously done her a disservice in the majority of the anime, if viewers are willing to look harder, they can still find the strong girl from Season 1 lingering throughout the show.
Plus, with the recently announced Sword Art Online: Progressive anime adaptation, it seems Asuna will finally be able to reclaim her rightful spotlight full-time, as opposed to when it's convenient for Kirito's character development.