She is said to be robed in white, and to take the form of a young maiden, in fact an angel.

She is said to appear to some chosen person, to whom she imparts some revelation; but, whatever that revelation may be, it is kept a profound secret from outsiders.
I remember that, just before the Zulu war, Nomkubulwana appeared, revealing something or other which had a great effect throughout the land, and I know that the Zulus were quite impressed that some calamity was about to befall them.

One of the ominous signs was that fire is said to have descended from heaven, and ignited the grass over the graves of the former kings of Zululand.

...

On another occasion Nomkubulwana appeared to some one in Zululand, the result of that visit being, that the native women buried their young children up to their heads in sand, deserting them for the time being, going away weeping, but returning at nightfall to unearth the little ones again." For this divine personage there is, therefore, authority, and the same may be said of most of the supernatural matters spoken of in these pages.