Earth, 21XX. The emergence of Adepts, humans with great powers, has thrown the world of the future into war. As groups fight for control and supremacy, QUILL attempts to save it.
Type: BlossomWith the discovery of new worlds, many Adepts have seen fit to flee this Earth, seeking refuge and safety elsewhere, where they won't be persecuted. Others, yet, have seen in that the opportunity to go places where they will be more powerful than the locals.
The Sumeragi Group would have their Earth become isolated from the Tree again at all costs, wishing to gain control of Earth without outside interference, and without a haven for Adepts to run off to or call allies from.
Eden, meanwhile, sees the outside world as both a refuge and a place to call for allies, as well as new technology. Their own conquest of Earth took a step forward, not backward.
QUILL is neutral, seeing in it great risks but also great potential. For now, they'll focus on fighting off Eden, Sumeragi and other threats.
As for the population and the rest of the world, it depends on where you go. Some countries are especially closed to outsiders, especially in wake of Adept uprisings. Others are a bit more welcoming and take advantage of the economics of other worlds and tourism. Some countries have actually turned peaceful as a result - seeing their Adepts flee to other worlds, they became thankful of the situation and embraced it.
Technology in this world is rather advanced: there are space stations and assorted superweapons, advanced battle armor and weapons, robotic drones and flying cars, etc. For ease of reference, it's very similar to what you'd find in the various main-timeline Mega Man worlds, Batman Beyond, Prequel-era Star Wars' Coruscant (minus the space travel, obviously), etc.
This world begins before the first Azure Striker Gunvolt game. The Muse is still under Sumeragi control (pending a Gunvolt applicant wanting to use that as his intro scene).
Eden, from Azure Striker Gunvolt 2, is around already (to make their characters relevant and playable). Their Grimoire technology is equivalent, instead of superior, to Sumeragi's Glaive technology, since they don't have the Muse fragments to power it yet. Their entry into Japan has been caused by off-world interference, allies and technology, rather than by Sumeragi's defeat (since that hasn't happened yet).
The Lifewave is a force of nature that connects all living beings of this world. A living being's connection to the Lifewave essentially dictates its intelligence and abilties. The Lifewave is composed of seven individual, gradually more powerful waves or "stages".
Most humans and animals are born connected to the first, second or third wave, with humans leaning towards the third and animals towards the first. However, when a being is born connected to the fourth or fifth wave, they may possess psychic abilities. These are the shamans, psychics and mystics of Earth's history, or the unusual monsters that would be spun into great legends. A being connected to the sixth wave possesses powers beyond even that.
Then there's the seventh, "Septimal", wave. Beings born connected to the seventh stage of the Lifewave possess incredible powers - control of electrons, warping space, bringing the dead back to life - christened "Septima" after the name of the wave. Children usually awaken their Septima before the age of 10. Humans connected to the seventh wave are usually refered to as "Adepts" in an attempt to dehumanize them.
The Sumeragi Group designed devices called "Glaives" using historical and mythological blades as basis. By transfering an Adept's "Septimosome", the source of their powers, into a Glaive, it becomes possible for them to have a normal life without being detected as an Adept, at the cost of being unable to use their powers without Sumeragi's authorization. Eden is working on its own similar technology, "Grimoires".