[Jim McDougall]

This is pretty interesting Joe, and seems like something put together using authentic components perhaps in Anglo-Egyptian Sudan. While the Mahdist period ended with the defeat of the Caliph at Omdurman (Battle of Kerrara) in 1898, the strong influences of the Mahdi remained.

The acid etched thuluth script seems right. The blade is short, but not unusual as kaskara were often shorter when worn in shoulder sling (see attached).

The guard is of course Ottoman, which was readily available in these times and the pommel atypical for kaskara, but known on a number of other weapon forms.
It is possible this was put together with traditional elements and a shortened blade for a faithful follower in later times. As always, there are suggestions of 'tourist souvenir' or something put together for sale in more recent times.
However, the authentic potential is always there as there are many anomalies in the Sudanese panoply of arms which remain 'outside the box'.

The thuluth script was indeed intended to imbue magic into the blade, and mostly swords and other tribal weapons were acid etched with this. This was I believe done mostly in the armory at Omdurman after the Mahdi's death in 1885 just after Khartoum. The script is typically not linear, that is, it is comprised of verses or phrases from the Quran sometimes with interjected other names, invocations. It was long believed this was simply decorative script but found to be authentically worded.
The example shown is of the type made at Omdurman late 1880s-90s for the Ansar (tribal warriors). The brass guard seems typical of these while other kaskara used iron (well described in Ed Hunley's outstanding work held in forum archives).