[@Liotrent] I was thinking something similar, that perhaps all dwarves were nomadic at some point in history and that these two tribes of dwarves split long ago for some reason. The Karaki dwarves used to be polytheistic. Maybe the Dunfender dwarves were always monotheistic, and that's what drove them apart all those long years ago?

The prophet Mhaza might have been influenced by the Dunfenders, copying but "refining" their faith.