In the 2170s, the Imperium had declined greatly due to conflict with the Rilnar. Annorax, a Krenim military commander and temporal scientist, sought to reverse this state of affairs by building a weapon ship that could erase targets from the space-time continuum. With it, Annorax destroyed the Rilnar and restored his people to glory. However, the elimination of the Rilnar indirectly led to a plague that devastated the Krenim, necessitating another temporal incursion. Over the next two centuries, Annorax erased countless civilizations from history, but could never achieve the full restoration of the Imperium that he desired. (VOY: "Year of Hell", "Year of Hell, Part II")