He seems to have been the leader or general of a force from Teotihuacan that invadaded the Maya heartland of the Peten. In 378 and 379 he oversaw the replacing of the kingss of important Maya states such as Tikal and Uaxactun with new rulers, some of them relatives of the Teotihuacan emperor, Spearthrower Owl.
Siyah K'ak' continued to act as a sort of overlord over such kings as Nun Yax Ayin in the region for some years, and his name is mentioned on monuments from many ancient cities of the central Maya lowlands, including distant Copan in Honduras .