A world with two extra continents, Atlantis and Lemuria, and with a whole lot of opportunities for adventure.
Type: BlossomA humanoid species ("atlantal" in their own language, plural "atlantali"), homo atlantalis, which comprised the native inhabitants of Atlantis and Lemuria. (In this world, the "atlantali" and their home continent is where the Atlantic Ocean gets its name, rather than ultimately being a reference to Atlas of Greek myth.) They are the creators of the Atlantean Grid, and theirs was the dominant civilization on Atlantean Earth until an event in 577 BC called the Atlantean Catastrophe. Most of them now live in Lemuria, but they also have a presence in Central America, Japan, and Australia, with a few scattered outliers elsewhere.
Many elves are elitists who call themselves "atlantali" even when speaking other languages; they claim to have a much more advanced culture and society than humans, although nobody else can agree what they actually mean by this. Some elves also claim to be the original form of life both on Atlantean Earth and throughout the entire World Tree, that they and their magic have a deep connection to the World Tree's existence, and that humans and the various human-adjacent beings are are merely a variation on them. The first piece of evidence against this is that none of the Atlantean elves' native languages are subject to the World Tree's translation convention, and they require interpreters in order to communicate with others if they don't know the local languages; the second piece of evidence against it is that they have very little presence outside of their native world, which is furthermore a Blossom rather than a Branch or anything else.
A vast network of structures and ancient computers which more-or-less covers the entire world; in its heyday, it had unparalleled unity between nature and technology, designed so that each would support the other. It contains all sorts of ancient technology, ranging from teleportation nodes, to treasures, to old weapons and magitech monsters.
In 577 BC, as a result of a computer virus, the entire network was taken offline in an event known as the Atlantean Catastrophe, and the system became openly hostile to anyone or anything which approached; to this day, the virus occasionally causes monsters to attack human or elf settlements, and there are buried parts of the Grid whose only sign is the presence of areas where nature struggles to survive. On the other hand, in Grid facilities which have been reclaimed and freed from the virus, nature appears to be stronger, with plants and animals becoming more healthy and living longer.
Atlantis: a roughly triangular continent which crosses the equator, directly between Central America and Africa. It contains the central control system of the Atlantean Grid, and was the center of elven culture and population before the Atlantean Catastrophe; for the most part, it is an inhospitable wasteland, with the Atlantean Grid's virus-driven defenses rendering it more-or-less impossible to survive there for more than a few days. Photographs from satellites and aircraft (or at least, the aircraft that have transmitted their findings before they were shot down the Grid's surface-to-air magic missiles) have shown that it is completely overrun by Atlantean magitech monsters, under which local flora and fauna struggle to survive.
Lemuria: an oblong continent which dominates the southern Pacific ocean, centered slightly further north than Australia. Its common name in English comes from an amusing misunderstanding about where and how lemurs evolved. Following the Atlantean Catastrophe, this is the main home of the elves.
Over the millennia, efforts have been made to reclaim or reverse-engineer the Grid for general use by both humans and elves, with mixed results. Nowadays, delving into the old dungeons and facilities of the Grid is a recognized career path, if not necessarily a respected one; licensed adventurers, both human and elven, have also found excuses to head out into the World Tree with everyone else, being that the world blossomed thousands of years ago on the inside, and it's just always been a part of life for everyone alive today. Parts of the teleportation network have been reactivated, allowing easy transportation, but due to the fact that the demand currently outstrips the supply, it is limited to those who are properly authorized (i.e. adventurers).
An elf-supremacist terrorist organization which has existed for hundreds of years. Who they are and what they are trying to accomplish remains to be seen. There are whispers that they are the successors to a much older organization, one which existed before the Atlantean Catastrophe; the reason they haven't already been routed by the human and elven governments is that they seem to have hacked into the teleport grid, and can spirit themselves away to places unknown.
A mysterious title of wandering adventurers and heroes who go around fighting rampaging Atlantean robots, plumbing deeper dungeons than the rest are capable of, and defending the world from the Dawnfall and occasionally traveling into the greater World Tree. They are characterized by Atlantean weapons which provide them with power and defenses against others, enhanced attributes, and protective uniforms.