The Grand War was a prolonged period of hostilities between the Hogedepi Imperium, Ksreskézaian Empire, and Tletkettoyi. It lasted from 4986 to 23947 ksepo (63205–67891 lky), with the Tletkettoyi entering the war as a third side after 8102 ksepo (63972 lky). The war was initiated and ended by genocides: first, the extinction of the Khúsak in 4986 by the Tletkettoyi, and then by the extinction of the Oksete and Tletkettoyi in 23947 by the Hogedep. For nineteen millennia on the Ksreskézaian calendar, the Expanse was embroiled in violence, depleting the region's diversity, population, and resources numerous times.

This section of the Museum is dedicated to understanding the many facets of the war, including the technology, tactics, and events that contributed to its inception, evolution, and ultimate outcome.