More from the “Campaign Ideas I’ll Probably Never Use” file

Another D&D campaign setting idea, this one combines Fallout and the Underdark:

An eon ago, there was the Cataclysm. We only have the stories to tell us what happened. Some say that wizards probed too deeply into the nature of magic and that something in the nature of the world simply snapped. Others say that there was a war in which such powers were unleashed that the world itself suffered as a result. Most stories agree that the sun itself changed in the Cataclysm. That is why we came Below – to escape it. Most of us simply lived within the caverns near the surface. We have traveled somewhat deeper since those early years – both for mining and to escape the range the fell beasts which now roam the desolate surface world. We have not gone too deep, however. We learned that lesson well. Some of us in the first few years travelled farther Below than the rest of us. For centuries, we thought them lost. The truth, we later discovered, was that they had been changed by their time in the deep earth. Those who traveled deep who were of the elven race, for example, were corrupted by a demon and have become her cultists…

Basically, take the standard D&D races and stick them into the upper levels of the Underdark. This will probably require giving them a boost in low-light/darkvision. The “standard” Underdark versions of PC races (Elf-Drow, Dwarf-Duergar, Gnome-Svirfneblin… maybe Human-Orc? and/or maybe Grimlock? and Halfling-Derro?) become twisted offshoots who delved too deep and were corrupted or otherwise changed.

Possible campaign ideas: (1) The re-connection with the “Deep” races may have been recently made. Diplomatic/trade relations may need to be set up… or perhaps there are the rumblings of a war. Alternately, perhaps the “Deep” races have encountered even more twisted things (Illithids and/or Aboleths, say) and seek an alliance against an enemy… or to use the PCs as a weapon against their enemies… (2) The PCs may need to scout out new, deeper areas for settlement. This could include a lot of exploration and conflict with the inhabitants of those areas. (3) Eventually, PCs may want (or need) to travel to the surface, which might be a place even more inhospitable than the Underdark.