The term Olgai tribe refers to the large clan of Vahnatai that has contacted both Avernum and the Empire. They are so named because their leaders are based in the city of Olgai. Led by the Olgai Council, they have been splintered and torn by internal strife and war since their initial contact with humans in 822 IE. The lands they inhabit are located far below Exile and commonly referred to as Vahnatai lands. They are most famous for their role in aiding Avernum in the Empire-Avernum War after the Empire stole three of their Crystal Souls. After that, they split into two factions - one led by the angry archmage Rentar-Ihrno and one led by the pacifist Bon-Ihrno. Rentar created the plagues that wrecked Valorim and later got her retribution on Avernum for their role in foiling her attack on the surface. Bon-Ihrno was killed by Rentar's minions and after his death his faction fell into disarray.
Much of the information gathered by historians and explorers about Vahnatai refers to the Olgai tribe - there are only two confirmed encounters with other clans of Vahnatai, and nobody has ever traveled to their lands.