Alien Codex (3.5e Campaign Setting)/Introduction
This campaign is unlike the star-trek and xenophobic or one species approach of most science fiction stories of the past. Instead taking the approach of many species relying on each other. There are three larger societies vying for control of the galaxy, The Fleet, Imperium, and Shadows. Once most of the galaxy was controlled by one Empire, this empire dominated and oppressed all in its way. But 500 years ago, a group of rebels were able to destroy the Empire’s power, and since that time the galaxy has continued to be divided. Decedents of these rebels have no home planet, instead coming from an organization of fleet ships called The Fleet. Whereas the remnants of the Empire and those wishing to reunify the galaxy are know as Imperium. Lastly, aliens and societies that live in-between the two or are outcasts are called Shadows.
This campaign has a strong futuristic combat focus, with futuristic weapons, bio-energy, vehicles (including star ships) and bots. Additionally, crafting and using technology is much improved. However, there is a de-emphasis on magic. There are still magic, but it is much weaker.
Xenoblooded and Xenotheric
Being from a strange place does have its perks, manifested through the xenoblooded and xenotheric subtypes. While not all aliens have these subtypes, many do, a biological requirement to survive on what are otherwise alien, hostile worlds or even purposeful genetic tampering on part of the races themselves.
The wealth of different innovations across the galaxy has created futuristic technology. This technology is far superior in design, and was eventually cataloged and numbered by the Imperium into FT Series equipment (standardization is one good thing the Imperium has done). All three societies have access to all weapons, but use the same naming conventions.
All alien technology can be scientifically explained, thus are treated as extraordinary within the galaxy. However, if found in a more primitive environment by comparison they would be viewed as magical (or psionic) – thus when in such worlds they can be treated as such.
Introducing Aliens in your Campaign
So you have decided to use aliens in your game. You can finally play out battles in space and everything, but what if your campaign is pre-existing and you cannot start out with the knowledge of aliens in the first place? You may decide that you wish to start introducing the aliens subtly, perhaps beginning with an abduction, or strange sightings. The PCs could discover ancient ruins which ends up projecting a beam into space and weeks later, discover it has called something down from the sky. This brings of the questions of how they will interact: will they be benign or vicious? Why have they come? Do they bring their entire force of a small scout ship? More importantly consider the possibility of your PCs getting a hand on alien technology. You may wish to deny its use, saying it cannot be used because it is too advanced. Alternatively you may want to allow them to use alien items, all the way up to starships. If such happens, your campaign setting may expand to other worlds, providing an even larger experience.
Politics, action, war, even ship-sailing themes can be explored using alien technology, as the PCs desperately attempt to figure out how to fix their ship as hostile beings chase them down, or their diplomacy attempts end up causing a much larger problem for their home planet. They may reach another land filled with alien gods, or end up hurling through time, only to arrive back home in the far future. The choice is up to you!