Not an ancient ethnicity but a people manufactured by conquest: from the early 1700s the Vungara and Bandia ruling clans absorbed dozens of small peoples along the northern forest margin into a belt of expansionist kingdoms, imposing one language and one political idiom across 800 km of savanna and gallery forest.
Not an ending: the Azande remain one of the larger peoples of Central Africa, now split across the DRC, the Central African Republic and South Sudan. The map hands off in 1885, as the colonial partition among Belgium, France and Anglo-Egyptian Sudan cut the Zande lands into three.
The standard scholarly history of the Vungara and Bandia kingdoms and the making of the Zande people; Clarendon Press, verified via Open Library /works/OL4790408W.
Northwestern University Press study of Zande society either side of the colonial rupture that ends this record; verified via Open Library /works/OL7391311W.