Segu represents the Bamana Empire (also known as the Segu Empire), which was an African Empire based in the Sahel, in modern-day Mali. Existing from 1712 to 1861, the Empire's Capital was at Ségou on the Niger River, the state was dominated by the Bambara people. Segu was one of a series of large Sahelian kingdoms which dominated Western Africa going back a thousand years to the medieval Ghana and Mali Empires.
Unlike many of the Empires of the Sahel (which were Islamic), Segu was a Pagan state (Ancestor Worship) and thus came into conflict with its mostly Muslim neighbors. This culminated in the events known as the Fulani jihads, in which the Muslim Fula people (called Fulbe in VIC2) rose up and established their own Islamic empires across West Africa (Sokoto being the largest). In the early 19th century the Segu Empire was broken apart by a Muslim revolt which resulted in the establishment of the rival Massina Empire. At the start of the game Segu and Massina are at war, with Segu weakened by having lost its Eastern provinces and Massina having a significant advantage with its Jihadi leader Seku Amadu. Historically, Segu was defeated by Massina, but managed to hold on in a weakened state until finally being conquered by the Toucouleur Empire in 1861, after which point the Bambara were forced to convert to Islam.
Segu is an Animist country with Bambara as the primary culture and African Minor also accepted.
In order to survive as Segu, you must first defeat Massina (a difficult task in the beginning) and from there try to conquer as big an Empire in Africa as you can in order to be ready when the Europeans come. With a fairly large population you should be able to defend yourself and eventually westernise, you are at least isolated from the coast, so the Europeans should be unable to attack you until the 1880s.
Tag: SEG - Segu
Note: There were several smaller Bambara-dominated kingdoms around Segu, but for game-play purposes these have been amalgamated into Segu. The name Segu was chosen for PDM because that's what the country is called in EU3, so it may be somewhat familiar to Paradox players.