Where: Dar Sila wandering sultanate (Chad)
When: unknown, early 20th century?
Who: Dar Sila Daju
Weapons visible: Kaskara
Source if known: "Dadjo Warrior Dahab, son of sultan Bakhit (Dar Sila)". From L'Afrique Équatoriale Française: le pays, les habitants, la colonisation, les pouvoirs publics. Préf. de M. Merlin.(published 1918)
Very interesting photo from a little known group.
Article on wikipedia.
There is a kaskara visible but also some sort of Arab looking saif with a very odd pommel that almost looks Tebu style.