Ruled the empire at its greatest extent — then smallpox killed him and split it.
Son of Topa, Huayna held the largest empire on earth — 2M sq km, 10M people. Moved court to Quito, fought Cayambi and Pastos for years, built fortresses and roads. European disease ran ahead of any Spaniard: smallpox swept Quito, killing Huayna and his chosen heir. Sons Atahualpa (Quito army) and Huáscar (Cuzco nobles) divided the realm and went to war (WHE).
Built Quito into a northern Cuzco with Coricancha replica, palaces and garrisons. Married Quito princess Paccha to bind Ecuador. Ruled from the north 10+ years — first Sapa Inca to leave Cuzco so long.
Smallpox — spread from Spanish Panama down trade routes — killed Huayna, his heir, generals and 200,000. Mummy carried to Cuzco. Empire split: Huáscar crowned in Cuzco, Atahualpa holds Quito veterans. Civil war kills 100,000 more.
https://www.worldhistory.org/Inca_Civilization/He ruled the world; a fever took it.— after Cieza de León