[Jim McDougall]

The conundrum term originally used here well describes this sword and in particular its blade. A conundrum is described as a paradoxical, insoluble or difficult problem; a dilemma.

I agree that postulation would be misplaced here, and the suggestions are presented as such to be considered rather than deemed any kind of assertion. While blades were indeed made locally in a number of locations in Africa, in this case the Sudan, there remained considerable numbers of trade blades throughout the vast networks of trade in Northern Africa. These were diffused and traded hands over long periods of time and through many means, and heirloom blades were often handed down in families or within tribal groups, resulting in remounting many times.

David's note on the blades typically produced in North African centers usually having three fullers is largely well placed, though at least one other form with deep central fuller is also known. The key point is that the blades, as previously mentioned, are invariably broadsword, that is with two edges.
With the fullers on this blade placed asymmetrically suggests of course that it was originally a backsword. As far as I know, no backsword blades would have been produced in Africa for the traditional native swords of North Africa, specifically the takouba and kaskara.
I will note that there is a variation of takouba using a curved blade, apparantly usually of European origin.

The native swordsmanship using broadswords favored slashing cuts, rather than thrusts, which is why broadswords were preferred. If this blade was a backsword form from an Arab or Indian source, and as David has pointed out, there are profound instances of weapons reflecting such influences and origins, then it does seem likely the back would have been ground away.

Very good point Ariel, on the very international presence of the eyelash/sickle mark, in fact that is the very reason it is so difficult to use in identifying blades. As you have well noted, it has travelled widely from its presumed origins in Italy, through trade into Styria and the Caucusus, and Central Asia and India as well. In Africa it is known primarily through trade blades, and as far as I know was not one of the images copied by the native smiths. The occurrence of these eyelash markings on African sword blades in most cases appears with others such as bracketing the familiar Andrea Ferara inscription, and occasionally others, but not singularly.
On the other hand, in Afghanistan, the sickle/eyelash mark does appear singularly and invariably, on the curved native blades of the paluoar. As noted, in the Caucusus, typically on Chechen blades, the marking denotes the blades known as 'gurda'.

All very best regards,
Jim