Duergar

 The dwarves' own drow, the duergar remain a bit more flexible in how you can utilize them in your campaign. In Golarion, they remain enslaved by an evil, slaver deity - but your take on them can always give them a different niche.

A particularly ambitious ashen dwarf oracle has decided that the world needs more duergars. To that end, he has enlisted the aid of several dero scientists - who are happy to work for him as long as there is a steady supply of fresh daywalker meat, which they experiment on with glee. This has resulted in an increase of disappearings in the dwarf-ruled settlement of Prestroyka, and an investigation is called for.

On the barren world of Druzga, all civilized life resides underground. For the past few decades, among the Dvergar, babies with mutations such as light skin, and resistance to the Sun's deadly rays have appeared at an alarming rate. What the public doesn't know, is that these so called "dvarfs" have united into a loose alliance, along with lightskin drow and fey-blessed svirfneblin. While the alliance has grown over the years, the only path to the surface leads through the lair of a massive crimson worm.

The Duergar of Antyss Abyss are said to worship the devil himself. True enough, as lords of the neighbouring lands dread duergar priests like no other enemy. Each fall, those priests come to the most downtrodden of villages, the dirtiest of slums, the bloodiest of the arenas. There, they find the poorest, the weakest and the most desperate. Each of them is offered a fulfilment of a single wish, supposedly coming from a god whose name must not be said out loud. The price is always the same: the recipient of the gift must place a single brick into the massive foundations of an unknown structure at the bottom of the Abyss. And yet, many who do so choose to remain underground, working menial jobs under cruel duergar masters. Each year, more and more good men flock to the depths, and the Lords' coffers and armies are begginig to thin.