Mbele

Mbele was one of the two ethnic groups involved in a civil war in the Angola-Zair border region in 1984. Mbele people are exploited by Buta in the Kungenga Mine, sometimes they're even taken as prisoners and forced to work as slaves. Mbele rebels are known to create child soldier squads such as the one Venom Snake rescues in 1984.

History
The civil war has been going on in that region since the early 60's. It was fought by two ethnic groups, the Buta and the Mbele. Originally those ethnic groups were almost identical, but after World War I their conflict started. After the war, their land was colonized by a European power, and it decided to give local control to the Buta. That split the two groups into rulers and subjects and the friction between them remained even after they won independence from Europe. In 1984 the Buta were still holding onto power and the Mbele rebels continued to fight back. The conflict was funded by locally mined gold, rare metals and diamonds. They've used the money from those to arm themselves, buy oil, and hire PFs.