From publisher blurb:
The spread of the Demon Lord’s shadow has triggered calamities and catastrophes that have upset the natural order of things, such that havens have become tombs, cities awash with blood, and monsters loosed in the countryside. No longer can people huddle in the dark; the time for hiding has come to an end, for the Demon Lord will devour all as it destroys the world. So, as the salamanders have begun to descend from their fiery peaks, so have the gnomes been dislodged from their cavernous homes to emerge blinking into the world they abandoned long ago.
This supplement reveals the gnomes, the second of the elemental ancestries for play in Shadow of the Demon Lord.