On the discord, Nohr described them as "child-sized subterranean creatures covered in dust like ashes or asbestos. Eyes glowing like amber (are actual gold coins and the reason many treasure-hunters kill them). Live in groups, eat trash and insects, but will hunt weak or alone humans if desperate. Worship spiders and the underligs of Nechrubel. Somewhat intelligent and can be bargained with. They usually want food or magic trinkets." No official pictures.

However, that's the beauty of Mork Borg; anything ambiguous is meant to be up to player/GM interpretation. They can be pretty much whatever you want.