Any history/folklore experts want to help me out?

I have some rather specific needs for a possible future project, and I haven’t been able to find what I’m looking for on my own as of yet.

Specifically, I’m looking for an African culture/people that:

A) Shares much of their mythology and folklore with the various Nguni/Southern Bantu peoples (i.e. the Zulu or Xhosa), and

B) Is largely extinct in the modern world, either because they were actually destroyed, or because they’ve largely assimilated into other local groups and no longer exist as a distinct people.

And yes, I realize that I’m asking for an extinct/largely forgotten subset of what amounts to the largest demographic in southern Africa. I didn’t say it was an easy task. 😉

I was thinking that one good place to start looking would be in the constituent tribes of the Mthethwa, before it was superseded by Shaka Zulu, but I haven’t found what I’m looking for as of yet. (Not that said group must date to that point; I just thought it was a viable era to begin looking.)

So, anyone out there willing and able to point me in the right direction? 🙂