The Visitors Saga Reference Book

To build an extended universe, some basic principles should be established:

1. The story usually pits two incompatible sides against one another (such as magic vs. technology). There's the residents, and the visitors. The residents are the inhabitants of the universe where the event takes place. The visitors are the outsiders, usually starting with a small number, recruiting people to their side, or with significant advantage over the residents.

2. Where the two forces clash, it is usually violently. The people caught in the crossfire are exposed to the powers of two universes that never should have naturally come in contact with one another. This caused mutation, or Corruption, which twists and transforms the victim in a variety of ways. Most Corruption mutations are adverse, but a few rise above and gain various powers. As a rule, the more devastating the exposure is (let's say a dragon vs. a nuke), the more powerful the Corruption becomes. It can also affect non-human entities. Corruption can be passed along to children, and hereditary Corruption is more effective, powerful and dangerous than acquired Corruption.

3. While it is possible for new, smaller splinter factions to emerge from one or both sides of the war, regular, prolonged exposure to the tools of the other side would slowly Corrupt the people involved. Each advantageous Corruption case has a primary power, and in time can develop a secondary power. Personal psychology plays a notable role in the metamorphosis.

4. The visitors forces are more likely to be Corrupted, just for being in a universe that isn't their own. But barring significant exposure, it would be too slow to notice and won't show any significant signs less than one year from arrival.

5. Two universes are considered to be compatible or incompatible based on the direction of the arrow of time in each universe. If a universe is perceived as going in reverse time (ie, their past is in our future), then both universes are severely incompatible and the rate of Corruption is at its highest should the two meet.

6.  A war torn world, after a certain threshold of Corruption, would be visited by a demonic entity known as Sita, which will consume the Corruption and the warring factions, growing stronger. Sita is ridiculously powerful, and is methodically manipulating incompatible universes into waging war against one another to satisfy her hunger.

8. Each resident universe is entered through a portal connecting to the visitor universe, which can open literally anywhere on the planet. Usually, it is quickly concealed by a tower, lighthouse, skyscraper, or other similarly shaped structure that allows the tower to access the nexus world.

7. Sita exists in the nexus world, from which access to all universes can be found, including identical universes where slightly different events have taken place. In the nexus, a small yet powerful resistance group made of a few survivors of dead worlds have utilized their Corruption to try and slow Sita down, if not stop her. So far, they are powerless to achieve that. Their leader is a mysterious man known as Archangel, who is known by the few that know him as the only man who faced Sita in battle and survived, with half a face, and most of his body, missing and replaced by cybernetic parts.

8. It is unknown how Sita feeds on her target universes, but it is known that it involves Corruption reaching a severe level that all battlefields fall to silence, which herald her arrival. After that, the planet becomes a husk which falls into an ever growing unchecked portal, which eventually consumes the rest of both connected universes and purges them.

9. There are a few constants: two or more incompatible forces meeting. Corruption due to exposure to the forces from two universes. Portal is concealed by a tower of some sort. Everything else is variable.

It is possible to tie the extended universe to several already established commercial franchises, although it is not advisable.

New principles can and should be added as necessary, if a majority of participants agree on it. This is an always evolving story, so evolutions are expected.