Bornu cavalry, Nigeria.
Bornu body guards for the Shehu (or ruler) of the Dikwa Bornu Emirate in Nigeria. The Shehu at the time would be Sanda Kyarimi, and the photo should then be from around 1917 to 1920s. This role was extremely important socially.
Riders all wear Yan Lifida (quilted armour although this is the Hausa term, not sure what it is in Kanuri as I only have a note for their term for maille).
Riders all have kwalkwali (helms, again a Hausa term the Kanuri term might be a variation of jaba) with what are likely brass headpieces. The decorative tops should be ostrich feathers.
The rider on the left carries a wide bladed takouba – the hilt appears leather covered.
The rider in the center with a visible sword, carries a brass hilted takouba, it is difficult to make out the blade profile.
Essentially knights of the Sahel! Some cavalrymen were equipped with cuirasses like the one below (from Heavy Armour in the Sahel: An Iron Cuirass from Northern Nigeria):
The takouba the prevalent sword type in the Sahel. This photo from takouba.org illustrates the diversity of shapes and hilt materials of takouba–various blade shapes, guard shapes, and pommel shapes, brass hilts, leather covered hilts, etc.: