The World Seed (世界の種子 sekai no shushi) is an in-game item with a distributive package called The Seed. It is a free beginner-friendly game engine and development kit with presets that allows easy creation of virtual reality worlds and management thereof as games, and supports the NerveGear and AmuSphere hardware for full immersion, or FullDive.

The Seed was developed by Kayaba Akihiko to replace the proprietary game frameworks, like the Cardinal System which Akihiko had developed while working for Argus and which had a licence fee that few could possibly afford. On the other hand, The Seed is intended for commercial and enthusiast use alike, and will run on private servers just as well as dedicated proprietary clouds.

Background

After Kayaba Akihiko — or, rather, his virtual copy — had helped Kirito save Asuna from Oberon by giving him the top level administrator username and password, Akihiko decided to request something of Kirito in exchange. He gave Kirito the World Seed item and said that he would like The Seed to sprout and grow, but ultimately left taking the decision to Kirito himself.

Kirito checked The Seed and made sure it was safe to use. In the end, he decided to upload it and make it available for everyone online. People all over the world hosted many VR worlds since then, and kept improving the assets Akihiko had left them to make even more games.

System

The Seed is a fully-featured game development kit with a full-stack toolchain required for easily creating a virtual reality world. It has a production-ready graphics engine and a audio I/O framework, as well as a light version of the Cardinal System once used to maintain the world of Sword Art Online by employing a powerful AI-based set of processes that would assist game development, automatically balance and debug its particularities.

Load distribution wise, The Seed is markedly different from the Sword Art Online backend framework that was tailored for centralized server service, and instead functions effortlessly by spreading the asset and computational resources across multiple affordable servers like, for example a "botnet" or cloud-distributed computational network would. That allowed the enthusiasts to adopt the engine with an even greater ease.

It is unclear whether The Seed's software was open-source, however it may be assumed that, at the very least, the game scripting and assets had compatible modification tools available, and it makes sense that the futuristic world painted in the series had finally given birth a truly universal game engine that did not need any binary changes.

Moreover, all games that are run on The Seed engine are mutually compatible to a great extent, allowing a player to freely transfer and convert their accounts (and sometimes keep the stats) between the Seed-based virtual reality massive multiplayer online role-playing games. There is an online hub for all the Seed-based worlds called The Seed Nexus that facilitates the search of the new flavors of the games.

Kirito, Asuna, and tentatively Yui have converted their Sword Art Online accounts to ALfheim Online. For Kirito, that resulted in an unexpected allotment of minor cross-game incompatibilities, mostly in the shape of a multitude of item placeholders where all his in-game items used to be, and so he could only see question marks. Somehow, Yui's Heart was transferred without a hitch, which could be potentially attributed to various possible processes. One of the versions is that on the file level, Kirito had managed to make a copy that included the environmental variables and files, thus having made Yui's environment a portable Docker-like package that was not dependent on any external assets and libraries. Another version is that since Yui's analogous systems were employed in ALfheim Online, there was a sufficient amount of compatible libraries and game resources to expedite Yui's deployment that did not even make assertions, or requests, for many of the assets of the previous game, which would incidentally explain her sudden shapeshift into a Navigation Pixie. Either way, it seems obvious that at least the hardware was compatible enough to allow for the same AI to function the same way on any underlying server system.

References

• World Seed - Fan Wiki
• Kayaba Akihiko - Fan Wiki
• Yui - Fan Wiki