The "rats in the sewers" campaign setting

[Turanil]

I just got this weird idea:

Our cities are inhabited by humans, who for the majority, hate rats. Rats, despite their weakness and lesser brains (this comment to explain my later idea), thrive in the cities' sewers and underground; human populations rarely bother about them when they remain in the sewers, so basically (I guess that) rats live quietly under the city.

So, now take this idea, but instead of rats you have humans... in a RPG world. So, there is a race of mighty beings, bigger, stronger, and most importantly far more intelligent than humans, who have built their own gigantic civilization (Also, lets say these are not elves or what not, but something more like aboleth, cthulu monsters, or else). Humans are seen as mere parasites who are left alone provided they do not bother these beings. However, humans don't live apart in their own separate realm; human live in the depths of the great beings' civilization, living off its remains as scavengers of sorts.

This could be a heroic-fantasy setting, a futuristic setting, or something sci-fi fantasy. Just imagine for example, that the great beings are all natural, extremely powerful magic-users. Well, some humans have learned magic in stealing (what they could understand) from these mighty beings. And when a human spellcaster cast a spell, he draws energies from these mighty beings in a similar manner a rat would steal food from a human's storage in a basement.

Comments? Further ideas to add to this?

 

[Stormborn]

There is a sci-fi story called "Rats in the Walls" that depicts somethign very similar to what you describe.

The caster as mana thief would, I think, need some mechanical work to back it up, but is an interesting idea.

 

[Henry]

Actually, maybe you could use the SpellThief from COmplete Adventurer as your Mana thief.

I don't know how sustainable it would be, because Rats, unlike humans in most settings, do not have a society. The PCs would have to be family-mates, perhaps, but even then Rats in sewers like pretty segregated lives from one another - there may be swarms of them, but they don't really look out for one another as humans generally do.

 

[Turanil]

because Rats, unlike humans in most settings, do not have a society

I used that more as a metaphor to explain my idea. I mean, humans who haven't developped a true civilization, but live in small tribes of scavengers on the fringe (or the undercity) of some mighty beings' civilization.

As I see it, this setting would be great with d20 modern+future+apocalypse. There is this strange incomprehensible alien civilization at PL8, plus many roaming monsters and hideous creatures that are either other parasites scavengers, or by-products of these unfathomable beings. There aren't millions of humans, just a few hundred scattered tribes of two or three dozens individuals. Some of these tribes are more evolved in terms of technological knowledge than others, but even if some Einstein live among them, they don't have the infrastructure and millions of people to develop their own society (and industry, etc.). They must live hidden from the mighty beings from whom they must scavenge, as these beings know about them but ignore them as long as they aren't bothered.

Well, if I were to run a d20 Apocalypse campaign, I would use such a homebrew setting. Magic would be allowed, with a special flufff: spells are in fact powered by an incredibly advanced technology of these beings, that human mages have learned to steal from (at personnal risk of being discovered).

 

[JamesDJarvis]

The old Palladium game Mechanoids (or was it Mechanoids Invasion?) used this theme. PCs were parts of bands of humans living on a vast starship avoiding and combating the Mechanoids that were masters of the ship.