In Terry Pratchett's Discworld:- === Although .Howondaland exists and tribes of black people are known to live there, the idea has not been developed further, save a few vague hints, and both the Prince and Kwa'Zululand do not (yet) exist in the Canon.
In the Pessimal Discworld:-Edit
Prince Canaan Banana N'Vectif is a brother of the Paramount King, and, in the manner of these things, as a potential usurper of the throne and as a loyal supporter in need of a prestigious reward (which coincidentally takes him well away from Home and the possibility of making a play for the Paramountcy), was given the plum role of Ambassador to Ankh-Morpork.
He therefore seeks to advance the national interests of the Zulu people from the Embassy on Brookless Lane, a typical Ankhian manor house which has been extensively rebuilt and redecorated on the inside to take out all those ugly un-Howondalandian square corners and to look as near as it can to the inside of a prosperous chief's long-hut in the Kraal.
He is a shrewd and experienced career politician and diplomat who knows he is under a disadvantage in Ankh-Morpork, a City which is inclined (reluctantly) to support the enemy state of White Howondaland, because (i) the white folk there are kith and kin; and (ii) because those bloody Klatchians support the Zulus, don't they, so we've got to support the other lot to maintain superpower parity in the region, Well-Known-Fact.
Even so, he can count on White Howondalandian Ambassador Pieter van der Graaf as a personal friend, or at least a man who knows and understands. Who especially understands a renewed all-out war between both countries could lead to mutually assured destruction.
Part of the Embassy is currently being rebuilt after what diplomacy describes as a "regrettable magical accident" brought about by the resident Witch-Finders behaving badly and getting on the wrong side of both the Guild of Assassins and Unseen University. Prince Canaan does not like the Witch-Finders, his country's rsident college of magic-users and informal secret police. But, as with Pieter van der Graaf and the Bureau of State Security, he realises he is stuck with a dangerous Embassy contingent only partly under his control. This has provoked one near-war on the streets of the City, and has the potential to cause more.
Embassy security is provided by a detached part-impi of warriors of both sexes, suplemented by a pride of were-leopards and the Witch-Finders. There is also a "niece war" going on, where, like his White Howandalandian counterpart, Canaan may call on the occasional services of his niece Ruth N'Kweze, a graduate of the Guild of Assassins. He also has a nephew, The Rev. Clement N'Fallibl, who is Chaplain to the Guild of Assassins. (Vetinari has insisted on absolute one-to-one parity at the Guild school between Boor and Zulu Assassin trainees, to prevent one side from gaining an advantage).
Prince Canaan maintains extremely friendly relations with the Klatchian Embassy, who represent Kwa'Zululand's long-standing ally and supporter.