The Multiverse RPG is, in it's core, a time-travelling, space-travelling, dimension-travelling action pack of exploring the multiverse. A campaign can visit any kind of time and space, in any universe. The game can stay in just one place, too. The information here concerns primarily the GM who want's to move his game from one universe to another. Players playing characters familiar with the device used to do this should also read on.
This chapter is aimed at the GM. It contains meta-information that is basically unknown to anyone. A charecter who could know these things for shure would have to be a very very ancient and superior being.
What is a multiverse and how does it work? Well, the multiverse is, really, an infinite whole of everything concievable. The multiverse is like an infinite stream of pure energy, chaotic energy in constant flux. In this chaotic flow, random swirls sometimes emerge. In the center of such a whirlpool an illusion of order is born. This illusion of order can cause some kind of "rules" to start to apply. This is how, for example, the laws of physics ruling our universe were born. The big bang in the beginning of our time was actually the moment when our swirl opened in the flow of the multiverse. Because the multiverse is infinite, there is also an infinite number of these swirls, and each can have it's own physical laws of reality.
The multiverse does not exist in any kind of "space" of it's own, so you can't "travel" over the border from one universe to another one. For things like time and space to even begin, physical laws must first exist inside a swirl. Each universe is thus some kind of a totality of laws in itself. You can not exit the multiverse because it is infinite and everything is a part of it. Some universes are like ours, they are very very big and have stars, planets, and galaxies. Some are entirely different. Any kind of physics, any kind of cosmology, and any form is possible. What that means is that, in theory, any imaginable world exists somewhere in the infinite swirls of the multiverse. Most of the chaotic multiverse can be ignored right away. Most of the swirls, too, because their content is too inconcievable. In this game you should concentrate mainly on parts of the multiverse that have something to offer for the characters of your game.
They way in which it is possible to move form one universe to another is to use some kind of threads that attach to points in the multiverse.
The key to getting from one time and place (in one universe) to another time and place (in another universe) is a device called, well, a device. Call it what you want, because you are propably physically unable to call what some other beings call it. The device comes in (m)any shapes and sizes. The only similarity between two devices is their function, well, to some extent.
What is this function, then? What the device does, propably, is that it separates a section of any time and place from any universe and creates a some sort of pseudo-dimension where the contents of this area remain until trasferred to another time and place... and universe. Devices are all activated mentally. There are never any buttons or such. Beings who do not know of the devices can almost never activate them, but anything that knows devices exist, and that this thingy they are in contact with propably is one, can usually activate it after some time and affort. The trick seems to be that you have to be certain that it will work. The more you doubt yourself, the device you are using, and wether it can transfer all the stuff you want it to, the longer it takes for the device to activate.
After you have activated the device, it seems to you like an area of existence around you has been separated from it's time and place. You are now in a room. The walls of the room are made of the material you'd expect them to be made of. It might be stone, metal, wood or any other material you would expect a room created by such a device to be made of. Somewhere on this wall is a doorway of the type you would expect to see. Behind this door is a control room, big enough to allow you to comfortably do what you need to do. Most modern people would propably see something resembling an airplane cockpit or an ocean liner's bridge. Some might see something resembling the bridge a sci-fi space ship. Beings who have seen real space ship cockpits would propably see something similar here. Someone medievalish might see a small library. Whatever you see, it is the most intuitive interface you could imagine for using the device's transport functions.
The control room, what ever it looks like, allows the user to perform the following functions in the easiest way he could imagine the first time he activated the device in question. The functions are selecting a destination, activating transport, accessing a log of recent device activity in current universe, recalling one (latest) previous address and getting statistics about wether the target location is a safe extraction point. You can hop around with the device checking random addressess out. The device requires a few minutes between jumps. In a safe location you can exit the control room and again mentally deactivate the device. After this the device extracts it's content to the specified place and time, softly pushing aside local materials and softly adjusting to local gravities. An arriving device is thus not much of a weapon, but when transferring stuff into the pseudo-dimension, they do cut sharp, real sharp. The device also propably adjusts you, more than you care to know. In any location where it is possible for you to exit, you always experience yourself the way you would in your original universe. Thus in a world full of Arnies you would still have normal strenght.
The most common type of device is the contact device. It usually looks like some smallish common object of a place and a time, but naturally, when you travel to a galaxy far far away, it might suddenly look like a mystical artifact from a galaxy far far away. A being must be in physical contact with the device in order to activate it. When activated, it transfers an area the shape of a perfect circle into it's pseudo-dimension. The radius of the circle, measured from the center point of the device, is usually two times the logest dimension of the being who activated the device. The control room door is located in the most convenient position possible. Of course, if you activate the device while buried in concrete, you are never getting to the control room. If you are buried in the ground, though, your best guess is to just start digging to any direction and the door will propably be exactly there.
A common type, too is the portal. They vary in shape and size, but function like a door into the pseudo-dimension. The form of the dimension is a straight endless tunnel in the shape of the portal. The control room door is on the left side wall near the entrance. When activated, you can see normally into the pseudo dimension through the gate. The gate will not close until whoever activated it is inside and decides to close it mentally. Once closed, the gate disappears from the time and place of departure.
Set-size devices are also known to exist. They can be any shape or size, and function by transferring themselves and anything inside of them into the pseudo-dimension. These devices usually have a logical place for a control room door. Often whatever doorway is used to enter the device, doubles as a doorway into the control room while the device is activated. One has to be inside of the device to activate it.
The following facts are general knowledge between beings familiar with the device. The control room never changes. The way it is the first time you see it is the way it remains forever with that device. Many different beings can travel using the same device, but only the one activating the device will "create" the control room. You can leave stuff into the control room and it will not disappear on it's own. It will also not appear in the control rooms of other beings or other devices. One fact becomes very clear after just a short while of goofing around with a device. Dialing random addresses gets you nowhere useful. An infinite amount of universes means an infinite number of useless addressess. Viable addresses are amongst the most valued of knowledge in the multiverse. The easiest (only) way to profit from a device without a book full of good addresses is to travel to the previous address in the devices memory. It propably points to somewhere where you can exist if some thing used it to get from there to where you are now.
The devices seem to use some kind of threads or links to travel to their destination, because when you return to an address you have visited previously, the place is the exact same, but time has passed. Usually from half the time you spent somewhere else to twice the time. This is thought to result from differences in how time passes in different universes.
Even though there's propably an infinite number of very big universes out there, some locations of space and time seem to be nicer than others. Atleast some locations are protected well enough to make you think so. Many species using the device are so different from us that there is no real way we could ever meet anywhere. Places where we could both survive a meeting are very rare. It's entirely possible for you to play a game of gas clouds if you want to. This chapter, though, covers mainly groups concerning carbon-based humanoids.
There a number of Protected super civilizations.
This backdrop works with many power levels from Joe Ordinary finding a device by accident to superhero multiverse police.