Earth (universe)

Diem's home universe is a vast ur-universe with unique properties. Notably, it doesn't seem to have a true name; its inhabitants refer to its world by their word for the element of earth, and they refer to the universe itself as simply "the universe," as if it's the only one. Thus, it has become known to scholars as "the Earth universe," or simply "Earth."

It is important to note that Diem was born in Earth, and he was the one who willed the Multiverse into existence; thus, in a sense, the Earth universe contains the entire Multiverse within it. It is entirely possible that Earth was the only universe in existence before Diem first formed the Multiverse, in which case its inhabitants would have been justifited in not bothering to give it a real name, as they thought of it as the one and only universe.

Cosmology
Unlike most universes, "Earth" seems to consist of one vast super-plane rather than a collection of planes. This plane, of course, contains Earth's world, along with an impossibly huge number of other world-like planets floating in a seemingly infinite void of empty space. Most such planets, especially those near Earth's world, have environments which are too hostile to support life; however, there is a remote possibility that some planets exist which could serve the same role as outer planes to Earth, or even function as alternate worlds.

Magic and Technology
Again, "Earth" is unique among universes in that it appears to lack magic of any kind. Surprisingly, society has continued to exist and even thrive despite this. The void left by a lack of magic has been filled on Earth's world by a startling proliferation of technology. Earth's inhabitants rely on incredibly complex machinery and a mastery of obscure alchemical reactions to produce technological marvels that fill the roles in their lives that magic items would in any normal universe.

Gods
The people of "Earth" have divided themselves into hundreds of religions, each worshipping one or more gods in different ways. Many of these religions are further divided into any number of sects or denominations. Earth has several theocracies, and its history is riddled with holy wars between religions.

All that being said, the most interesting thing is that there is no real evidence that any of these gods actually exist. Since the universe is devoid of magic, clerics recieve no divine power from their worship, and none of these gods walk the world in the flesh. Through Earth's history, people occasionally have claimed that one god or another has spoken to them personally in private, but none of these claims have ever been substantiated. Since Earth doesn't seem to have any outer planes, it's highly dubious that any such gods exist at all; however, the origins of this universe are still unknown, and it must have come from somewhere. If it was created by gods, they would have to live on one of the distant planets floating in Earth's spatial void and almost certianly have little to no contact or influence with the world.

Races
Interestingly, despite its vastness, "Earth" only has one sentient race: humans. While this is not unheard of among universes, it is somewhat uncommon, as most universes boast several sentient races. Diem himself is of the Earth human race, which could explain why humans are the one constant race that always seems to exist on every world without fail.

More disturbingly, since Earth humans are an entire race of people just like Diem, it's entirely possible that each of them has willed his or her own Multiverse into existence as well. Our Multiverse could simply be one of billions of sister Multiverses all contained within the ur-universe of Earth.

History
See: a textbook.