As comfortable as it is to think that Greyhawk, no matter how many years pass, will largely stay the same - Geoff will always be threatened by giants, Iuz will always be scheming in his wasteland of a kingdom, and the Scarlet Brotherhood will always be a mysterious and nebulous force in the south - sometimes the best thing for the sandbox is to throw a really big rock into it: knock down a few castles, kick some dirt into somebody's eyes, and watch a little chaos - or perhaps a lot of chaos - ripple its way through things. Every now and then, I think it behooves a DM to do such a thing, to break the campaign setting just a little bit with an event well outside the control and scope of the adventuring party, and just watch what changes to the landscape take place and how the players/characters are forced to react.
Of course, the key to this is not to force author edict changes upon the campaign simply because you can, but, as I said, to change things up and every now and then yank out the support structures and familiar rules of the players, force them to adapt and survive. After all, one of the core tenants of old school play is to challenge the players, not just the characters, is it not?
When I first started putting this article together, it was going to include other topics - ice ages and glaciers, civil wars, invading conquerors, dead gods, and the like, but then I realized that in order to cover everything that I wanted to, it would end up being an intolerably long wall of text. So, in an effort not to drive away my 2.5 readers, I'm going to break this up into separate topics over the next few days and see where it leads.
One of the most basic ways to do that is to, quite literally, throw a really big rock at the setting. A meteorite, comet, or other bit of space debris can very minor repercussions, or cause massive devastation across the landscape. A moderate sized meteorite (say, a few kilometers across) landing in the wilderness will kick up enough dust and debris into the atmosphere that will, even though the impact site might be a thousand miles away, cover all the land in a second darkness if you'll forgive me cribbing notes from the recent Lord of the Rings atrocities. The first result will be a widespread fire from the heat of the impact, burning out large portions of the wilderness and forest, driving animals, logging communities, and monsters from their places and into the more civilized lands. Previously non-hostile elf tribes may suddenly find themselves pushing into human farmlands in order to find a place to survive and weather the storm of goblins, orcs, and trolls driven out of the dark forest by the flames. After the fires, the dust in the air would dim the sunlight, leading to a drop in temperature. Crops begin to fail, leading to famine, starvation, disease, and, inevitably, war as various duchies, baronies, and kingdoms fall upon each other in a desparate bid for survival.
Such a large impact would certainly be cause for sweeping changes throughout the campaign world. Reduced temperatures and crop failures (not to mention species extinctions later on) would not be limited to the immediate area. Peoples on other continents may suffer and never suspect the cause. An impact of a similar sized body close to or directly in a major population center would be a truly horrific event, an event that could wipe out a location the players thought of as a safe haven, an island of calm in the wilderness.
Of course, this is not to say that such an impact need be large. A bit of falling debris the size of, say, a wagon or bull might be just enough to destroy or gravely damage a particularly important building or few blocks of the local metropolis, killing old contacts of the PC's, or old enemies, paving the way for a power struggle as people dig their way out of the destruction. Or perhaps an even smaller body may strike, doing little damage, but causing significant changes. A small meteorite the size of a dwarf, for instance, crashing into some thoroughly explored portion of Castle Greyhawk opens up the entrance to a previously unknown section of the dungeons, perhaps leading to a lost laboratory or library of the Mad Archmage, perhaps even throwing one of old Zagyg's experiments into high gear again after centuries of dormancy.
Before I get off the subject of rocks, I feel the need to point out at least one more possibility with things falling from the sky: something brought along with the falling stone. Back in the high days of the Ravenloft campaign, there was a brilliant little monster workup that - though a direct steal from Invasion of the Body Snatchers - was nevertheless a wonderful monster. The Doppleganger Plant. I shouldn't even have to explain what it does. Suffice to say that, at least from the perspective of a player (where I first experienced this monster) the creature is truly a marvelous thing in the hands of a good GM. In fact, the Dungeon adventure in which the plant was introduced (#54 I think, or thereabouts) is truly excellent.
Of course, malign plant life isn't the only thing that can catch a ride in from outerspace. Perhaps the meteorite carries with it a strange and seemingly uncurable disease that spreads through the slums of WaterDeep after a falling star burned down a dissused warehouse near the thieves' guild headquarters. Perhaps, instead of just one, dozens, or even hundreds of stones fell, and around each one, a contagious anti-magic field, spread via close human contact. Wizards and clerics would be forced to quarantine themselves lest they lose all their abilities. And then again, who could forget one of the most classic stories of passing meteorites/space debris? Or, for that matter.
More Little Treasures
2 years ago