Ghana - Climate change and the conflicting Berber groups led to the downfall of Ghana.
Mali - There were more fights of succession and this lead to civil wars. This was due to the patrilineal traditions, which were unstrict and where the son succeeds in finding the next king.
Songhai - Similar to the fall of the Mali Empire, they also suffered from civil wars caused by succession. However, it was much worse because the king's brothers would kill the kings and in some cases, the kings protected themselves by executing all their brothers. Moreover, a neighboring military started to invade the Songhai Empire, weakening the Songhai empire. This was the last West African Empire.
Hope this helps!
