"DEMIURG BROTHERHOOD RESPONDING"
- – From the Tau Empire trailer for the Battlefleet Gothic vidya
The Demiurg are a client race of the T'au Empire and are described as short, rocky humanoids using huge mining ships to brave asteroid fields to mine.
Squats, straight up an alien species different from the abhuman known as Squat, though the confusion is quite common. Reportedly they were created specifically as a compromise for fans who wanted the Squats back, though GW ended up doing very little with them anyway. The most we ever see of them is in Battlefleet Gothic as auxiliary fleets, and that’s about it. As a side note, they sound frickin awesome though.
Their lore in BFG is one big fat reference to Homeworld Bentusi, not just in name, but the whole concept of ancient spacefaring race of traders, every fleet a brotherhood, and they are so hardwired to their ships that ship damage results in loss of captain mental capacity. And just like the Bentusi, Bentus'la, how Tau call them, have taught the young ones how to build ion cannons (for 400 resource units?)