Huáscar

Inti Cusi Huallpa Huáscar, or "Sun of Joy" lived in 1503–1532 and was emperor of the Inca empire from 1527 to 1532 AD, He succeeded his father Huayna Capac and brother Ninan Cuyochi. Both of whom died of smallpox while they fought near Quito. 
On the death of their father and their older brother, the empire was divided between the two surviving brothers, Huáscar and Atahualpa. Huascar got the major part of it with the capital Cusco, and Atahualpa the northern parts, including Quito (now the capital of Ecuador). For a couple of years, the two brothers reigned without problems. Huascar demanded that Atahuallpa swear an oath to him. Atahuallpa refused and the civil war began. Atahualpa's commander lead armies of 100,000 men. About 60,000 men supported Huáscar. This demonstrates the numerical potential of Incan armies. The war was uncompleted, but Atahualpa had a clear advantage when Francisco Pizarro arrived. It was partly due to this civil war that Francisco Pizarro was successful.