Final answer:
The warrior king was the most significant type of ruler in Kanem-Borno, as evidenced by their military innovations and control over trade routes sustained by their military power.
Step-by-step explanation:
In determining which type of king was most significant in Kanem-Borno, it is essential to consider the historical context and the roles these leaders played. The empire of Kanem-Borno, known for its military prowess, significantly benefited from the trans-Saharan trade, particularly in enslaved people.
The military innovations and the importation of firearms from North Africa during Mai Idris Aloma's reign point to the importance of the warrior king archetype in sustaining and expanding the empire's power. Furthermore, the control over the desert caravan routes played a crucial role in Kanem-Borno's dominance, much of which was enabled by the empire's military strength. Thus, historical evidence suggests that the warrior king was the most significant type of ruler in the context of Kanem-Borno.