Insofar as campaign ideas go, this has to be one of the simpler ones I've devised, but it is easily one of the most mentally prevalent I've had in a while. Based in a song that I heard by Barns Courtney, I was inspired a long time ago and with each listen of the song since, I've had ideas of how a story could develop around a dwarven empire.
After some quick research, I decided to base the story line in the Great Rift, or Underchasm, as it's known now.
I have based it in Underhome], or what remains of the vast empire that surrounded [[The Great Rift. Underwatch, is become a home of the Iron Guard, where they muster, train and launch their incursions from.
Being that the empire was destroyed during the Year of Blue Fire (1385 DR) and in our story, it has been slowly rebuilding by a banding of several kingdoms of dwarves, humans, halflings and other humanoids within and without the region.
Most specifically, a duinian platoon of warriors that had traveled from Citadel Adbar, to happen upon a dying kingdom in need.
The players are employed by the Iron Guard, a force not unlike the Nights Watch from Game of Thrones, but less criminal doings and more honour bound servitude. Originating as Citadel Adbar's military, the incredible loss of dwarven life in the south, coupled with the many wages that have continued to hammer upon the dwarven peoples, eventually gave way to those who would seek out alliances with other clans.
Since the Great Rift became Underchasm, it has taken on a new level of threat, with East Rift providing most of the staging for the existing delvings and defense points, Underhome as denoted in the map above sits at the edge of the massive pit.
From Bhaerynden to The Great Rift to Underchasm there is an absolute ocean of current content to consume and consider so naturally you can expect I'll forget massive amounts of it and stumble hard for a session or two while I get my bearings in this new region of Faerûn.
Some light reading in preparation for this campaign includes this fantastic piece of work: https://matthewfenn.ipage.com/nj-pbem/data/Races/DwarfInfo.htm.
For language reference, folks in the area speak a range of languages as noted here.
As with any campaign, there's some spin up time while players are figuring out their characters; in due course, everyone will know what they're playing and the sort of character they want to portray, as opposed to a wash of some colour or stereotype.