Blue Lander,
The knife handle looks like Kassala style, with the design similar to what the Rashaida Arabs in the region. Could be painted all black to simulate ebony or totally black piece of African Black Wood.
See man holding similar handled knife in link.
http://www.alamy.com/stock-photo-B8M...n-Kassala.html
Have no experience with blade markings as on your knife. Could be a maker's mark or has some symbolic meaning. Some blades like yours are made from steel shipping crate bands and are very sharp!!
The sheath isn't of the Kassala style, but more from the upper White Nile Valley. Kassala knives are/were exported throughout much of Sudan so I suspect that the knife and sheath were mated by a buyer maybe in Khartoum.
Hope this helps,
Ed