Stem The Vermintide
It had been six years since the shrieking madness of demons rang out from the Underdark. A relative quiescence held over the deep - but now many think it unnatural.
Menzobarrenzan lay in ruins after the conflagration of abyssal violence laid waste to the drow capital. Many expected redoubled raids - rebuilding requires labour, for which the drow turn to slavery. But no slavers descended. Even the svirfneblin, the few that wandered out from their depths, whispered of an unnatural still - as if some great menace watched in shadows. Of the duergar, we heard nothing.
Many whispered rumours of a resurgence in shapeshifters, of gangs of wererats trading fortunes for seemingly innocuous trinkets, demanding only silence. These rumours never rose above a whisper - any conspiracists disappeared, their apartments filled with vermin.
Then Darkhold, the burgeoning capital of an Zhentarim ascendant, was taken. Having grown rich from defending the realms first from Tiamat and then Demogorgon and their ilk, Darkhold had grown from holdfast to a small metropolis - growing as large Neverwinter in the three decades following the great battle at the Well of Dragons. Those that escaped speak of an eruption of sickly green fire, and a seething great mass of ratfolk bearing mystical armaments.