The following is a section from the Campaign Saga Overview, intended for GMs. This section is about adapting the campaign to a different setting. There are some spoilers in here, so if you plan to play in the campaign saga, I recommend you stay out.
[sblock]
Tweaking the Setting
War of the Burning Sky is intended to fit into any world, but we use a baseline setting as the core of the campaign saga. If you want to place this campaign saga in an existing setting, you might simply say that Ragesia and the lands around it lie far from the realms the PCs have previously experienced or in a distant part of the world. Or you might prefer to find an area that closely parallels the terrain and nations of the campaign saga.
Ragesia could be any militant nation, though it should sit in a nice middle point of a region where it is strong enough to threaten lesser nations, but not so strong that the rest of the world would have risen up to put it down.
Nations and Cities: The conflict of the campaign saga involves two major nations - Ragesia, a Lawful Evil empire with human and orcish armies, and Shahalesti, a Neutral nation with elf-heavy armies.
When looking for nations in an existing setting, Ragesia’s stand-in could be any evil nation able to field a large enough army to potentially conquer several of its neighbors. Shahalesti’s stand-in should be slightly weaker than Ragesia, somewhat militant but not evil. The two nations should be neighbors or fairly close. The events of the adventures one and nine focus on a terrain bottleneck between the two nations - in this case a defended mountain pass - but any restricted terrain could work, such as an isthmus or a narrow strip of temperate coastline on the edge of a trackless desert.
The rest of the surrounding nations can be whatever you want, though you will want to try to keep a similar geography in the relation between Ragesia and Dassen, so that the fire forest of adventure two can provide an actual shortcut. It’s a small enough area that it should not be hard to add it.
There could be many smaller nations involved in this conflict, but whatever you do, make sure that the conflict doesn’t stretch far enough that nations far more powerful than Ragesia and Shahalesti get involved. The PCs should feel like they’re the underdog, and that they have a big fight ahead of them. Other nations should not be interested enough to simply sweep in and save the day; that’s for the party to do.
Major NPCs: The two biggest sparks of the war are the vacuum left after the fall of a powerful warlord, and the desire to retrieve the artifact that let him come to power in the first place. The specifics of the warlord aren’t too vital. Emperor Coaltongue’s stand-in just needs to be feared and cunning, and to have commanded armies, but his age, race, and even class could certainly change. He might have only recently begun his march to power, and he might only have had the Torch of Burning Sky for a short time.
Leska and her anti-magic inquisitors are a fairly large component of the campaign setting, but any group of ominous minions work. The inquisitors could be a recent development, rather than a deep institution of Ragesia. Leska’s stand-in just needs to be the ‘hands-off manipulative genius’ style of villain.
Having a group of non-good elves who aren’t drow might not fit a lot of settings, so any group that mixes warcraft and spellcraft can be substituted. Their ruler Shaaladel’s stand-in should still be motivated by a sense of moral superiority, not some generic ‘evil intentions.’ He needs to be highly charismatic, and have convinced people to do things they might normally think to be wrong, which means they might choose not to follow him if given the option.
Pilus can be directly affiliated with any nation looking to sieze power, so he’s perhaps the easiest to fit in. Likewise, the leaders of the Lyceum academy were not world movers and shakers until the start of the conflict.
Immortality and the Aquiline Heart: Leska’s tie to the Aquiline Heart actually gives her relatively little, since any high-level leader would have access to true resurrection, but the Heart gives the players a memorable way to strike a seemingly invincible foe in her weak spot. The myth of the Aquiline Heart can be a famous old legend that people only half believe, like the tales of the Holy Grail, or it could be isolated to Ragesia. If you substitute an existing legend of the setting, you might lose some of the phoenix imagery in the later adventures, so try to find something that would involve fire so it ties in well with the ‘burning sky’ part of the title.
Trillith: The trillith are a totally new group, and since their existence is relatively unknown it should be easy to fit them in. You might need to alter the timeline of the Mother of Dreams somewhat, to make sure she keeps her ties with the creation of the Torch.
Adventure Locations: Any setting has enough uncharted terrain that it shouldn’t be hard to work in a fire forest, a monastery, a psychic temple, and an underground prison. Don’t worry about having to use famous locations from a setting. Just because the PCs don’t personally fight the battles in a well-known city doesn’t mean that the battle isn’t happening. The conflict should appear massive, much bigger than the PCs. Of course, players like to feel a little bit legendary, so at least in the climax adventures, try to use notable locations.
A few adventures, particularly The Mad King’s Banquet, Mission to the Monastery of Two Winds, and O Wintry Song of Agony are intended to give you as GM a lot of leeway as to the specific location of battles. You just need to decide where a strategically-important battle would occur, then send the PCs on the particular missions of the adventure, which are intended to be pivotal to the conflict.
[/sblock]
I'm running one of my playtests in Forgotten Realms because the players are huge fans, and they thought the idea of Obould Many-Arrows ending up as a warlord for Thay was ridiculous but entertaining. I'll have to look over some Eberron and Greyhawk texts again to make sure I'm not getting any details wrong, and hopefully by the end of the week I can give you suggestions for all those settings.