Sword Art Online tore through the world of anime when it premiered in 2012, popularizing isekai and making it into a viable sub-genre.  Though isekai anime had existed before, after Sword Art Online it was impossible to get through a single season of anime without at least one isekai series, whether the characters were stuck in a game or not.

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Over the years, the popular light novel adaptation has expanded out to have multiple television series and films, with Sword Art Online Progressive getting a movie adaptation next. With nearly a decade of stories behind it, it can be easy to get lost in the terminology and lore that's been built up without some explanations.

10 What Is The Seed?

Aincrad from Sword Art Online

The Seed is the entire reason any VR MMO can exist in the first place. It’s a set of programs that allow players to experience all five senses within a game, allowing FullDive to be possible. Made by Kayaba Akihiko, this set of programs is actually free to access and use to build a world on top of. All the VR MMOs are connected through The Seed, which allows players to transfer their character over to a new game while keeping their stats, though not their items.

9 What Is A Beater?

Kirito sad from Sword Art Online

This term was basically about players identifying all beta testers for Sword Art Online who took advantage of their additional knowledge and were basically referred to as cheaters. Kirito pushed the existence of this term in the aftermath of the defeat of the first boss in the game when players began to turn on beta testers. This lead to Kirito being seen as both a loner and one of the least popular people playing the game for a time, though it was meant to take the focus off most of the beta testers and aiming it towards him instead.

8 How Many Games Are There?

SAO ALfheim Online

Across the World Seed, there are multiple games that make up the Seed Nexus. There are multiple games in the world of Sword Art Online, and the viewers only see a small handful of them over the course of the game. What's known so far though is there are three: Sword Art Online, Alfheim Online, and lastly, Gun Gale Online. Project Alicization is not a game and thus does not count in this number.

7 Why Is Dual Wielding Special?

Kirito with Dark Repulser in Sword Art Online.

Dual Wielding is a technique that exists in Sword Art Online that belongs to Kirito alone. The player is able to use two blades at once, allowing them to use the sword skills of two different blades, which is what makes them so powerful.

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As viewers would later learn, Dual Wielding is a skill given to a player with the absolute fastest reaction time among all the other players, and whoever manages it will be capable of fighting against the boss on the 100th floor.

6 What Is A Unique Skill?

Kirito versus Gleam Eyes from Sword Art Online

Different from other skills, Unique Skills are skills that specifically belong to just one player in a game. In the world of Sword Art Online, there are only ten Unique Skills in the game, which means that only ten players could ever achieve them. By the end of the original Sword Art Online story, only two characters attain a unique skill. The first goes to Heathcliff, who’s granted the Holy Sword for being the strongest player. The second goes to Kirito, who’s given Dual Blades for being the player with the quickest reaction time.

5 What Is Full Dive?

sword-art-online-asuna-nervgear

The idea of Full Dive is connecting to a virtual world. This is done via a large number of ways, but specifically, it’s done in the original series through the NerveGear project. It allowed the player to both send and receive signals into a VR MMO so they can experience the world as they would experience real life. The original NerveGear contained the ability to emit microwaves that would kill the user if they died in the game or someone removed the helmet, and it’s this way that Akihiko Kayaba was able to trap 10,000 players in his game.

4 How Does Yui Exist?

Yui, Sword Art Online in a digital realm

Yui was an artificial intelligence that was originally created by the company responsible for Sword Art Online. She existed as a means to help players who were struggling with mental health issues, but she was locked out of acting in the game once Akihiko took over.

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Eventually, she was found by Kirito and Asuna, who adopted her as their child because she’d forgotten who she was thanks to the alterations in the system. Once she recalled her identity, she still saw Kirito and Asuna as her parents but gained the ability to access the Game Master mode and mess with the code of the game.

3 What Is A Fluctlight?

Alice, Sword Art Online

The concept of a Fluctlight is actually rather complex. Essentially, Sword Art Online’s universe introduces the concept of how to distill the entire human consciousness down to a light particle. This light particle can be translated into a quantum field, referred to as a Fluctlight. At the next level NerveGear is capable of capturing this Fluctlight and transferring it into a VR system, basically connecting the player’s soul to another world.

2 What's The Secret Behind Project Alicization?

Eugeo and Alice standing in the dark between a tree

Project Alicization is a special project being worked on by the Japanese government specifically for improving Japan’s military. They aimed to create bottom-up artificial intelligence, artificial intelligence that can think outside of the box. This involved cloning the Fluctlights of newborn humans and raising them up inside of an artificial world. The goal is to create an AI capable of pushing past the initial programming and thinking for themselves, forcing them to face various trials to push them to that level.

1 What Is The Cardinal System?

Sword Art Online Cardinal

The Cardinal System is the larger version of The Seed, and was also created by the creator of Sword Art Online, Kayaba. This system is developed to allow the game to manage all the systems within the SAO game. It creates NPCs and a working economy, while also creating new quests and automatically fixes any major problems in the game. It’s the Cardinal System that fixes programming errors like quest problems, and it was also used in Sword Art Online’s rip-off Alfheim Online in the second half of the original series.

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