is a Japanese light novel series written by Reki Kawahara and illustrated by . Originally released as a web novel on Kawahara's website from 2002 to 2008, the light novels began publication under ASCII Media Works' Dengeki Bunko imprint in April 2009, following them approving his request to publish it. The series takes place in the 2020s and focuses on protagonists Kazuto "Kirito" Kirigaya and Asuna Yuuki as they play through various VRMMORPG worlds, and later their involvement in the matters of a simulated civilization.
Multiple spin-offs have been released, including Sword Art Online Alternative: Gun Gale Online, Sword Art Online: Progressive, and Sword Art Online: Girls' Ops. Several adaptations into other media have been produced, including more than ten manga and an anime television series, which aired for three seasons from July 2012 to September 2020; a television film was released in December 2013. Anime film adaptations have been released in February 2017, October 2021, and October 2022. Several video game adaptations and board games have also been released.
Sword Art Online themes include the dangers associated with virtual reality and allowing an external device to control a person's brain. The early volumes, as well as the anime, have received praise for the premise, world building, and the bond between Kirito and Asuna, while the pacing, writing, and treatment of female characters have been criticized; Kawahara has expressed regrets about the latter and critics felt that his writing improved in later volumes. The series has frequently ranked in Kono Light Novel ga Sugoi! and has 30 million copies in circulation, making it one of the best-selling light novels. It has also helped popularize web novels, VRMMORPG, and isekai fiction.
Synopsis Setting The light novel series spans several virtual reality worlds, beginning with the game, Sword Art Online (SAO), which is set in a world known as Aincrad. Each world is built on a game engine called the Cardinal system, which was initially developed specifically for SAO by Akihiko Kayaba, but was later duplicated for Alfheim Online (ALO), and a consolidated package is later given to Kirito in the form of the World Seed, who had it leaked online with the successful intention of reviving the virtual reality industry. A third world known as Gun Gale Online (GGO) appears in the third arc and is stylized as a first-person shooter game instead of a role-playing game, and is the main setting of Alternative Gun Gale Online. It was created using the World Seed by an American company. A fourth world appears in the fourth arc known as the Underworld (UW). The world itself was created using the World Seed as a base, but it is as realistic as the real world due to using many powerful government resources to keep it running. A fifth main world called Unital Ring (UR) was formed under mysterious circumstances from the merging of all of the Seed MMO worlds, and is the main setting of the Unital Ring arc along with the Underworld.
Plot
In 2022, a virtual reality massively multiplayer online role-playing game (VRMMORPG) called Sword Art Online (SAO) was released. With the NerveGear, a helmet that stimulates the user's five senses via their brain, players can experience and control their in-game characters with their minds. Both the game and the NerveGear were created by Akihiko Kayaba. On November 6, 10,000 players log into SAO mainframe cyberspace for the first time, only to discover that they are unable to log out. Kayaba appears and tells the players that they must beat all 100 floors of Aincrad, a steel castle which is the setting of SAO, if they wish to be free. He also states that those who suffer in-game deaths or forcibly remove the NerveGear out-of-game will suffer real-life deaths.
A player named Kazuto "Kirito" Kirigaya is one of 1,000 testers in the game's previous closed beta. With the advantage of previous VR gaming experience and a drive to protect other beta testers from discrimination, he isolates himself from the greater groups and plays the game alone, bearing the mantle of "beater", a portmanteau of "beta tester" and "cheater". As the players progress through the game Kirito eventually befriends a young woman named Asuna Yuuki, forming a relationship with and later marrying her in-game. After the duo discover the identity of Kayaba's secret ID, who was playing as "Heathcliff", the leader of the guild Asuna joined in, they confront and destroy him, freeing themselves and the other players from the game.
In the real world, Kazuto discovers that 300 SAO players, including Asuna, remain trapped in their NerveGear. As he goes to the hospital to see Asuna, he meets Asuna's father Shouzou Yuuki who is asked by an associate of his, Nobuyuki Sugou, to make a decision, which Sugou later reveals to be his marriage with Asuna, angering Kazuto. Several months later, he is informed by Agil, another SAO survivor, that a figure similar to Asuna was spotted on "The World Tree" in another VRMMORPG cyberspace called Alfheim Online (ALO). Assisted in-game by his cousin and adoptive sister Suguha "Leafa" Kirigaya and Yui, a navigation pixie (originally an AI from SAO), he quickly learns that the trapped players in ALO are part of a plan conceived by Sugou to perform illegal experiments on their minds. The goal is to create the perfect mind-control for financial gain and to subjugate Asuna, whom he intends to marry in the real world, to assume control of her family's corporation. Kirito eventually stops the experiment and rescues the remaining 300 SAO players, foiling Sugou's plans. Before leaving ALO to see Asuna, Kayaba, who has uploaded his mind to the Internet using an experimental, destructively high-powered version of NerveGear at the cost of his life, entrusts Kirito with The Seeda package program designed to create virtual worlds. Kazuto eventually reunites with Asuna in the real world after thwarting an attack from Sugou and The Seed is released onto the Internet, reviving Aincrad as other VRMMORPGs begin to thrive.
One year after the events of SAO, at the prompting of a government official investigating strange occurrences in VR, Kazuto takes on a job to investigate a series of murders involving another VRMMORPG called Gun Gale Online (GGO), the AmuSphere (the successor of the NerveGear), and a player called Death Gun. Aided by a female player named Shino "Sinon" Asada, he participates in a gunfight tournament called the Bullet of Bullets (BoB) and discovers the truth behind the murders, which originated with a player who participated in a player-killing guild in SAO. Through his and Sinon's efforts, two suspects are captured, though the third suspect, Johnny Black, escapes.
Kazuto is later recruited to test an experimental FullDive machine, Soul Translator (STL), which has an interface far more realistic and complex than the previous machine he had played, to help RATH, a research and development organization under the Ministry of Defense (MOD), develop an artificial intelligence named A.L.I.C.E. He tests the STL by entering the Underworld (UW), a virtual reality cyberspace created with The Seed package. In the UW, the flow of time proceeds a thousand times faster than in the real world, and Kirito's memories of what happens inside are restricted. However, when Johnny Black ambushes and mortally wounds Kazuto with suxamethonium chloride, RATH recovers Kazuto and places him back into the STL to preserve his mind while attempts are made to save him. During his time in Underworld, Kirito befriends Eugeo, a carver in a small village of Rulid, and helps him on a journey to save Alice Zuberg, his friend who was taken by a group of highly skilled warriors known as the Integrity Knights for accidentally breaking a rule of the Axiom Church, the leaders of the Human Empire. He and Eugeo soon find themselves uncovering the secrets of the Axiom Church, led by a woman only known as "The Administrator", and the true purpose of Underworld itself, while unbeknownst to them, a war against the opposing Dark Territory is brewing on the horizon. They meet Alice, now an Integrity Knight, and though she does not remember them, Kirito helps her remember her true identity: a form of true artificial intelligence known as A.L.I.C.E. In the battle against the Administrator, Kirito manages to slay her, though Eugeo dies in the process, to Kirito's dismay.
Meanwhile, in the real world, conflict escalates as American forces raid RATH's facility in the Ocean Turtle in an effort to take A.L.I.C.E. for purposes unknown. Two of the attackersGabriel "Vecta" Miller and Vassago "Prince of Hell" Cassalstake control of two Dark Territory characters as they unite the Dark Territory's inhabitants to aid them. With help from all his friends, Kirito manages to stop the attackers as well as foreign players lured by Vassago, and safely extract A.L.I.C.E. from UW, who gains a physical bodywith Gabriel and Vassago being killed both virtually and physically in the process. However, Kirito does not log out in time before the flow of time is restored and spends 200 years in UW (about 2 weeks in the real world) with Asuna, who stayed behind for Kirito. After awakening they have their memories of 200 years in underworld removed under Kirito's request, though RATH employee Takeru Higa secretly keeps a backup consciousness of his 200-year self, who have unknown plans for the Underworld.
One month later, Kirito, Asuna, and the others have their accounts forcibly migrated to Unital Ring, a new VRMMORPG which incorporates locations from all the other environments they previously visited, and investigate the cause while meeting some familiar faces.
Production Reki Kawahara wrote the first volume in 2001 as a competition entry for the 2002 ASCII Media Works , but refrained from submitting it as he had exceeded the page limit; he instead published it as a web novel under the pseudonym Fumio Kunori. Over time, he added three further main arcs and several short stories which, like the first arc "Aincrad", were later adapted into the light novels. Kawahara originally released the novel on his website from 2002 to 2008. In 2008, he participated in the competition again by writing Accel World, this time winning the Grand Prize. Aside from Accel World, he was requested to get his earlier work, Sword Art Online, published by ASCII Media Works. He agreed and withdrew his web novel versions.
For the protagonist Kirito, Kawahara was asked if Kirito's personality and character were based on his own; he answered that he usually does not put aspects of himself into his characters, and jokingly remarked: "but if I had to say there was a point of similarity between Kirito and myself, it is the fact that neither of us are good at forming parties. We [both] tend to play solo in these games a lot." He also noted that the female characters in the story were not based on anyone he knew in the real world, stating: "I don't usually make a character, setting, or anything before I start writing. As I write the story, the girls become what they are now. So, somehow, I don't know exactly, but somehow, my subliminal idea or some hidden emotion creates the characters to be strong and capable." He added that he wrote the series to demonstrate that he views online gaming not as a social ill or escape from real life, but rather decided to show games in a more positive light in his light novels. Kawahara also noted that the character of Asuna might have been created a little too perfectly.
Publication