The Sword Art Online Season 4 release date be far offer over the horizon considering that the third season finished in September 2020 and the SAO: Unital Ring book sequel hasn’t been completed yet as of the fifth book in the new series.
What’s more, the Sword Art Online: Progressive movie anime series that released in 2021 was a reboot of the original anime, not a direct sequel to Alicization’s ending. (Please see the new article for details about the SAO: Progressive story.)
But announcements concerning the Sword Art Online: Alicization anime episodes and the Sword Art Online: Unital Ring light novel series gives fans a glimpse into the future of Kirito, Asuna, Alice Schuberg, and other SAO characters.
What we do know for certain is that Aniplex intends on adapting the entire SAO series into anime. The third season adapted the entire Alicization arc and the direct book sequel to Alicization is already up to the fifth book in the series. While Unital Ring probably won’t be longer than Alicization, it should be the final ending of the entire SAO story.
What does Unital Ring mean for Sword Art Online Season 4? A-1 Pictures director Manabu Ono once stated in an official interview that he had spoken with Aniplex staff around the time the SAO: Ordinal Scale movie was being screen-tested and “they were planning to adapt the entire Sword Art Online series.”
While Ono did not specifically mention SAO: Unital Ring or the possibility of Sword Art Online Season 4, keep in mind that Kawahara had already publicly announced Unital Ring when this interview was published.
Therefore, it’s not unreasonable to assume that a Sword Art Online: Unital Ring anime is in our future. The only question is when the fourth season will release and the answer is largely up to Reki Kawahara, the creator of the SAO series.
The third season was streaming on Hulu, Funimation, Crunchyroll, and HIDIVE. The third season was divided into four cours that adapt the entire Alicization arc.
A cour is a three-month unit of broadcasting time based on the physical seasons, so four cours means the four quarters of a full year. But all four cours of Sword Art Online Season 3 were not aired consecutively.
Anime studio A-1 Pictures released 47 episodes in total for the Sword Art Online: Alicization anime adaptation. The first half was 24 episodes while the second half, Sword Art Online: Alicization – War of Underworld, had 23 episodes.
The finale, Sword Art Online: Alicization War of Underworld Part 2 Episode 11, released on September 19, 2020. The new SAO: Progressive anime was announced the same day.
- Updated February 02, 2022: Added SAO Unital Ring 5 info.
Updated December 9, 2020: Added SAO Volume 25 postscript note from the author. Changed release date predictions based on climax info.
Updated November 30, 2020: Added SAO Volume 25 illustrations.
Updated November 9, 2020: Added Sword Art Online Volume 25 cover art.
Updated September 27, 2020: Added SAO Volume 25 release date and SAO: Progressive Volume 7 release time frame.
Updated September 19, 2020: Sword Art Online: Progressive anime confirmed!
Updated September 14, 2020: Added more SAO: Unital Ring details and restructured the story.
Updated June 8, 2020: SAO: Alicization final season release date confirmed!
Updated April 10, 2020: Sword Art Online: Alicization Final Season delayed! Added Unital Ring 3 details.
Updated February 25, 2020: Added the exact date for the Sword Art Online: Alicization Final Season anime.
Updated December 28, 2019: Added time frame for last season of Sword Art Online: Alicization – War of Underworld. Added more Unital Ring book news.
Updated October 14, 2019: Added SAO Season 3’s number of episodes and Blu-Ray details.
Updated September 6, 2019: Added exact release date for Sword Art Online: Alicization – War of Underworld.
Updated March 31, 2019: Added SAO Season 3 hiatus confirmation. Added War of Underworld trailer and other details.
Updated December 7, 2018: Added more Unital Ring spoilers, light novel image gallery, and Season 3 hiatus details.
Updated November 16, 2018: Added new Sword Art Online Season 4 spoilers, SAO Volume 21 cover art, and exact title name for Unital Ring 1.
This article provides everything that is known about Sword Art Online Season 4 (Sword Art Online: Unital Ring) and all related news. As such, this article will be updated over time with news, rumors, and analysis. Meanwhile, let’s delve down into what is known for certain.
Sword Art Online Season 4 release date: Unital Ring anime possible by 2023?
As of the last update, Aniplex, A-1 Pictures, or any company related to the production of the anime has not officially confirmed the Sword Art Online Season 4 release date. Nor has the production of an anime sequel been announced.
Once the news is officially confirmed this article will be updated with the relevant information. In the meantime, it’s possible to speculate about when, or if, the Sword Art Online Season 4 premiere date will occur in the future.
Predicting the Sword Art Online Season 4 release date is a bit difficult since the number of volumes for Unital Ring is unknown. The one thing we know for certain is that Kawahara has strongly stated that he hopes it will be shorter than Alicization, which was 10 books long.
SAO Volume 21: Unital Ring 1 released on December 7, 2018. Volume 22, which released on October 10, 2019, was four side stories while Volume 23, which released on December 10, 2019, was the direct continuation of the Unital Ring story. Sword Art Online Volume 24: Unital Ring 3 was released in May 2020, while Unital Ring 4 came out on December 10, 2020, and Unital Ring 5 on October 8, 2021.
Assuming that Unital Ring is shorter than Alicization, Reki Kawahara could conceivably be done with 8 books by 2023 at the absolute earliest. And that’s assuming he begins pushing himself by releasing two books per year on average.
But it’s possible the SAO: Unital Ring story will be much shorter than Alicization. In the SAO: Unital Ring 4 (Volume 25) postscript notes, Kawahara provided a minor spoiler and then indicated that the Sword Art Online: “Unital Ring Arc” climax was approaching. And Unital Ring 5 certainly does offer a climactic moment.
That could mean that Unital Ring could be less than even 8 books. Assuming that’s the case, it’s possible Sword Art Online: Unital Ring 6 (Volume 27) could be the final ending, which means the book series could be over by late 2022 or early 2023.
Anime projects take years to develop, so the earliest likely premiere date for SAO Season 4 is between late 2023 and 2025.
Of course, it’s also possible that Kawahara could release only one new Unital Ring-focused book a year, which would mean the wait for the SAO: Unital Ring anime could be quite long indeed if he’s targeting SAO Volume 29 for the ending.
As discussed later in this article, creating a Moon Cradle movie makes sense, but another option would be to adapt Moon Cradle as a single-cour Sword Art Online Season 4. That would mean Unital Ring would be Sword Art Online Season 5.
In combination with the SAO: Progressive anime, creating a Sword Art Online: Moon Cradle movie makes sense since it would fill in the long gap between the third season’s finale and the completion of Unital Ring.
Sword Art Online: Alicization light novels compared to the anime
SAO started life as a novel contest entry for Dengeki Novel Prize that ended up being self-published online as a web novel because the story was too long. From 2002 through 2008, Kawahara published on his own website a series of side stories and a direct sequel that built on the success of the original premise.
The series was eventually picked up Kadokawa’s Dengeki Bunko imprint and adapted into a light novel series starting in 2009. (Unfortunately, the web novel is no longer available online.)
Kawahara had many ideas besides SAO. From 2004 through 2009, he wrote a web novel called The Isolator (Zettai Naur Kodokusha), which told the story of a teenager named Utsugi Minoru, who was given a superhuman power when various extraterrestrial life forms come into contact with the human species. He also entered the Dengeki Novel Prize contest again with the Accel World story and won.
Kawahara relied on many time gaps in the original SAO story because the writing contest required that he had a solid ending, not a cliffhanger or a “to be continued” ending. Not satisfied with the way that the Aincrad story arc turned out, he rebooted the first two volumes as a spin-off called Sword Art Online: Progressive (which also has a manga adaptation). Progressive follows Kirito and Asuna as they cleared Aincrad one floor at a time.
Volume 6 released in May 2018 and it told the story up to floor 6. The Sword Art Online: Progressive Volume 7 release date is scheduled for Spring 2021.
The English translation of the SAO light novel series is being published by Yen Press. By the time the final part of the third season of the SAO: Alicization anime began airing, the English light novels were only up to Sword Art Online: Moon Cradle, which released on April 21, 2020.
The English Volume 21, Sword Art Online: Unital Ring, released on January 19, 2021, with the English edition quickly catching up.
In addition, there are several active fan translation projects that are already up to Volume 18, which is the ending of the Alicization story arc.
The third season of the anime adaptation is based on the Sword Art Online: Alicization arc, which is the longest story arc thus far. According to the author’s afterword in light novel Volume 18, Kawahara actually wrote the entire Alicization story in web novel format starting in January 2005 and finishing in 2008.
Years later, Kawahara wrote a web novel called Cradle Of The Moon, which is an Underworld side story that takes place shortly before the ending of Alicization during the time gap when the fluctlight acceleration was maxed out. The Alicization story was adapted into light novel volumes 9 through 18, while volumes 19 and 20 were called Moon Cradle part 1 and 2.
The third season of the anime adaptation adapted the entire Alicization arc. The pacing was a bit faster in comparison to previous seasons since there were 10 books to cover in comparison to the eight books adapted by the first two seasons.
As might be expected, many details from the light novels were condensed for the anime adaptation. For example, Kawahara noted on Twitter that the anime’s opening episodes skimmed over the “reason why the current artificial Fluctlights cannot be used as weapons.”
“In animation, it is necessary to compress explanation parts greatly, and we can not convey all the logic,” he tweeted.
Already, fans are starting to make comparisons between the light novel and the anime. The biggest difference in Episode 1 was the action scene set in Gun Gale Online, which showed off a GGO Asuna. That scene was completely anime original, but it was a nice addition which gave a break from the info dumping that took place in the latter half of Episode 1.
Fans also noticed that the TV show seemingly skipped the Zakkaria Sword Arts Tournament of Volume 10, Chapter 3 so Kawahara offered an apology.
“I’m sorry that the Zakkaria Arc was handled through flashback only, but it is necessary to be selective with episodes even though the season is four cours as there are 10 books,” Kawahara said. “I think two books per cour is the limit if you want to do the adaptation faithfully, but I think Zakkaria was the biggest cut.”
By Episode 24, the anime had finished the ending of Volume 14. The SAO: Alicization Episode 25 of the War of Underworld story arc opened with the story events of Volume 15.
The ending of the anime’s story shifted back to the real world and show what happened leading up to events on Ocean Turtle. Sinon was competing against a player named Subtilizer in the fourth Bullet of Bullets tournament of the Gun Gale Online game. It turned out Subtilizer was connected to everything happening.
Episode 47 finished by adapting the ending of Volume 18: Alicization Lasting.
The bad news is that Kawahara currently has not released enough books for Sword Art Online Season 4 to be produced immediately following the third season. The good news is that he’s hard at work on the sequel.
Will there be a Sword Art Online: Moon Cradle movie?
The biggest question mark is what Aniplex plans on doing with the two book volumes related to Sword Art Online: Moon Cradle. Although Moon Cradle takes place chronologically before the end of the Alicization arc, the Alicization anime will not be adapting the Moon Cradle arc.
In writing the story, Kawahara said the Moon Cradle web novel was originally “structured to be readable as an independent fantasy story with some character names in common (with the original works).” Therefore, adapting the light novels in chronological order would seriously disrupt the flow of the story in the Alicization anime.
Without getting into major spoilers, Moon Cradle involves multiple SAO characters spending many years worth of virtual time within Underworld. The plot is self-contained and only indirectly relevant to Unital Ring so far (see the spoilers section below for more details).
But how do so many years transpire? In Episode 1 of SAO: Alicization, Kirito explained the concept of Fluctlight Acceleration, which allows a human FullDiving via the Soul Translator to experience time at an accelerated rate. This time dilation factor is usually maxed out at 1,500 in order to avoid filling up the Fluctlight memory, but near the end of Alicization, the Fluctlight Acceleration is cranked up way, way past the safety limits.
Before certain SAO characters are ejected from Underworld, Rath decides to delete all memories accumulated after the Fluctlight Acceleration rate was increased. That means Moon Cradle is a story about a lifetime of memories spent in Underworld that the characters no longer remember once they’re in the real world.
Moon Cradle is similar to Ordinal Scale in that it’s not necessary to watch the latter movie to understand the plot of the main anime series. Therefore, it would make sense for Aniplex to adapt the story as a Moon Cradle movie since it would give audiences something new to watch until Sword Art Online Season 4 is released.
Sword Art Online: Unital Ring sequel began releasing in 2018
In early 2017, Kawahara had promised “one more big arc” that will go “back to the real world.” Starting with Sword Art Online Volume 21, the author plans on developing a new type of game idea that’s different from The Seed games (Alfheim, GGO, etc.), Underworld, and the augmented reality Ordinal Scale.
This means the new story arc requires that Kirito, Asuna, and all the other SAO characters start over. The story is also new ground entirely because it’s the first SAO story arc that is not based on a web novel.
Kawahara also left a message at the end of the Cradle of the Moon web novel which stated that the “battles of Kirito and Asuna, Leafa, and Sinon and others, and Alice will be continued” when “they are their descendants once again take up swords” in the “final, greatest battlefield: The War of Intelligence Space.” Whether or not that was a hint about the upcoming story arc remains to be seen.
Bikini Alice goes to the beach along with Asuna and the other girls. — Pic credit: abec
Kawahara eventually announced that the new story arc will be called Sword Art Online: Unital Ring 1 and that it will be a direct sequel to Alicization. The author explained that Unital Ring’s title is similar Ordinal Scale because both titles are a reference to a mathematical term, but that doesn’t mean the two story arcs are linked in any manner.
When fans asked if SAO: Unital Ring will be longer than Alicization, he replied, “Oh… I strongly hope not.” In recent interviews, Reki implied that Unital Ring might be the final ending when he declared, “If the anime is going to continue, my light novel will be over after Alicization.”
For Dengeki Choukansha Fair 2018, a bonus short story called The End of the Summer and the Straw hat was released. (Warning: This story is set in-between Alicization and Unital Ring 1 and it contains one major spoiler concerning Alice.)
The release date for SAO Volume 21 happened on December 7, 2018. SAO Volume 23: Unital Ring 2 released on December 10, 2019, while SAO Volume 24: Unital Ring 3 released on May 9, 2020, and SAO Volume 25: Unital Ring 4 on December 10, 2020.
The Sword Art Online Volume 26 release date was October 18, 2021. It was titled Sword Art Online: Unital Ring 5.
Sword Art Online: Unital Ring anime spoilers
The year is 2026 and it has been half a year since the Ordinal Scale incident. Kirigaya Kazuto (real-life name of Kirito) was attacked by Johnny Black, a former member of the Laughing Coffin murder guild, at the end of June before Summer Break. Although Kirito spent years of virtual time in Underworld, he woke from his coma in the real world on August 1, 2026.
After a long recovery, Kirito returned home and it’s now only ten days away from him becoming eighteen years old on October 7th. (Coincidentally, the Alicization anime premiered on Kirito’s birthday.)
The prologue for SAO Volume 21 makes a big deal about highlighting the respective birthdays of Kirito and Asuna, as well as Kirito’s musings about how his life could have gone differently if his parents had not died in a car accident when he was a baby. Since his real name was Narusaka Kazuto before he was adopted, Kazuto comically believes he may have used the gamer character named Naruto instead of Kirito.
Asuna will also be 18 soon, as well. Since both main SAO characters will soon be of legal age, it would not be surprising if the Unital Ring story arc features a Kirito and Asuna wedding. Although, Alice may have something to say about that since she and Kirito grew very close during their time in Underworld.
Since emerging from Underworld, Alice has lived in the real world with a humanoid mechanical body complete with schoolgirl clothing. When Alice met Kirito’s parents she treated them as if she were Kirito’s wife in the way she addressed them.
Asuna was incensed and threw down the gauntlet, promising to end the love feud ceasefire they’d established in Underworld. All poor Kirito could do was attempt to hide from the two girls chasing him down.
Kirito and Asuna had many of their memories of Underworld suppressed but not completely forgotten. While Kirito is upset that he can only remember mere fragments of memories from Underworld, Asuna quips that she’s okay with losing some memories since she believes he was busy getting into trouble with other women. Needless to say, Kirito probably wishes he could reboot his love relationships, not just his memories.
Back in the real world, Kirito and his virtual daughter Yui are discussing what sort of birthday present to buy for Asuna. Since being designed by Kayaba Akihiko, creator of SAO and The Seed, Yui has grown greatly as a self-aware top-down artificial intelligence. It’s even hinted that Yui’s capabilities may have grown to the point that she’s in control of Japan’s supercomputers.
Kirito eventually decides to dive into New Aincrad, the recreation of the floating castle. Maintained in Alfheim Online, the floors are now open up through Floor 50 and players are slowly working their way up to the top. But Kirito desires quiet so he can focus on catching up on school homework so he transports to the small log cabin that he and Asuna originally built on Floor 22.
Almost finishing up on his report, Kirito hears the sound of footsteps and mistakenly thinks the blue-haired Asuna has entered. Instead, it’s the blonde-haired Alice, who has become a Caith Sith cat knight in Alfheim because it was the easiest way to become a dragon-flying Dragon Knight.
Alice had announced herself to the world in a grand speech at a press conference and now she’s advocating human rights for AI. She’d gained notoriety with gamers for the way she chewed out PKers for the way they behaved. But she also enjoyed relaxing in Alfheim since it was similar to Underworld.
Due to Fluctlight Acceleration, 200 years had already passed in Underworld since Integrity Knight Alice Synthesis Thirty had vanished. When Kirito, Asuna, and Alice last snuck intoUnderworld, the technology had developed to the point that people were living in space colonizing planets and Pilots, not Integrity Knights, were flying mechadragons. All three characters were regarded almost as a legend by the newest generation of AI humans living in the Human Empire.
Fluctlight copies of Kirito and Asuna had lived on in this world (the events of Moon Cradle). They became Underworld’s “King and Queen of the Stars” and Kirito believes his virtual counterpart had died 30 years ago in virtual time. But the Rath corporation had reset the Fluctlight Acceleration so that time in Underworld was running at the same pace as reality.
Despite being disconnected from Underworld for so long, Alice hoped to resurrect her sister, Selka Zuberg, who survived in Deep Freeze inside the Central Cathedral. Alice also hoped to re-hatch the dragon siblings and raise them again.
Eventually, Asuna logs in and joins Kirito and Alice inside the log cabin. Alice and Asuna are outwardly civil toward each other but Kirito definitely notices the mood change when the two women are in the same room together.
Without warning, Kirito’s wooden cabin is shaken by a massive earthquake, which should be impossible in the virtual realm. Everyone is shocked when the sky turns red with a hexagonal pattern that perfectly mirrors the system-wide event that trapped everyone in Sword Art Online.
Suddenly, Aincrad begins crumbling and the chunk of land containing Kirito and Asuna’s loghouse plummets towards the ground. Kirito remembers the Ordinal Scale incident and how Professor Shigemura recovered the original Aincrad on the old SAO server in Argus’ basement. This original Aincrad serves as Yuuna’s grave now, but since it’s difficult to access that server Kirito decided to focus on making the loghouse in the ALO Aincrad their one true home.
In order to protect the loghouse, Asuna suggests using their wings to the change the trajectory of the falling landmass so that it lands in a river. They succeed and the newly created loghouse island bounces around in the river until it enters a forest.
The warnings from the red hexagonal sky disappear and just as suddenly Kirito, Asuna, and Alice all lose the ability to fly. Kirito tries in vain to pull up the assistant flight controller only to crashland into the river while curled up in a ball and he loses half his health points.
When all three swim to the surface of the water, they discover that Kirito and Asuna have lost their elf ears but cat ears Alice is here to stay. With all three no longer capable of flight, they swim to the shore in search of the loghouse. That’s when they noticed they remained wet, which was unusual since wet clothing usually dried within seconds in ALO.
With a sinking feeling, Kirito tried summoning the menu system multiple times – even trying with his other hand – but the menu didn’t appear. Instead, he discovered he needed to draw a circle clockwise with his right index and middle finger.
Unlike ALO’s square menu, this action called up a light purple ring menu that showed him his status, skills, equipment, storage, quests, map, communication, and system. Old messages are deleted and their Friends List is empty so they can’t message anyone. Kirito also cannot contact Yui even though she’s technically his navigation pixie.
All three quickly realize that they’re listed as Level 1 characters even though ALO does not have levels. Kirito looks in his storage only to discover that everything is wiped out except the Holy Sword Excalibur and the Black Welt (the sword created by Lisbeth). The girls are similarly missing most of their items and Asuna theorizes that they only were allowed to keep their two most prized possessions.
With a huge sigh of relief, Kirito and Asuna find a door-shaped submenu for logging out. So, while Unital Ring has changed the world, they’re apparently not locked into a death game like before. But Kirito quickly realizes they’re stuck in a survival game since the stats are tracking their thirst and hunger. It’s now up to Kirito and friends to find out what is going on in both the virtual and real world.
What does it all mean? The title Sword Art Online: Unital Ring may be a reference to worlds uniting. Sword Art Online: Alicization blurred the lines between realities based on the way events transpired in both Underworld and Ocean Turtle. In the case of Unital Ring, both the virtual world and the real world may experience an event similar to the original SAO.
The beginning of the prologue also offers a major hint, as well. What Kirito does not realize is that Higa Takeru, the chief developer of the Soul Translator, not only saved the physical bodies of Kirito and Asuna, he also saved a copy of Kirito’s 200-year-old soul.
This copy of Kirito spent years living in Underworld and he startles Higa with a prophecy that the doors to reality would open. This Star King also makes this cryptic message:
“I’d be known in Underworld as the Star King, just as Asuna would be known as the Star Queen. Kazuto and Asuna rediscovered all of Quinella’s secrets, used them, reforged the world, eliminated all barriers between civilizations, united the four kingdoms with the monsters living in the Dark Territories… And then conquered space itself.”
Before the scientist can do anything Star King escapes the Ocean Turtle lab virtually, jumping onto the internet and disappearing into the United States. Star King believes the future of Augmented Reality and VR lies in America and he’s also trying to track down a certain individual who displays real-world abilities similar to Accel World.
Why is this relevant? During the opening paragraphs of Sword Art Online: Unital Ring, Star King and the soul of Kayaba Akihiko apparently have a virtual chat. They are discussing the future of the Nexus, the whole interconnected network of VR worlds that sprung forth from The Seed. Simply acting as observers, Star King and Kayaba are uncertain whether the Nexus will wilt and die or evolve to the next stage: Unification.
In addition, book publisher Kadokawa has confirmed that Unital Ring’s story will involve a new mysterious survival game that’s set in a new world. What’s more, all of the virtual worlds built with The Seed program (Alfheim Online, Gun Gale Online, and many more) have suddenly all merged, or unified, into a single VR game world!
Does that also mean Unital Ring will have VR worlds and reality collide? Unfortunately, anime fans have quite the wait until Sword Art Online Season 4 sees our reality. Stay tuned!