A Krenim city in 2374
The Krenim Imperium is a military power in the Delta Quadrant. Located in spatial grid 0-0-5, the Imperium's weaponry was chroniton-based, making them a formidable foe, as their torpedoes existed in a state of temporal flux, allowing them to penetrate deflector shields with ease.
The Imperium's temporal science had advanced to such a state that by the 2170s they were able to develop a temporal weapon-ship, capable of erasing a target from the space-time continuum. This ship was used to eliminate the Rilnar, who were the greatest enemies of the Imperium. However, the removal of the Rilnar led to a plague that almost destroyed the Krenim completely. In a bid to restore his lost race, the vessel's commander, Annorax, removed countless civilisations from history. After 200 years of trying, the Imperium was still a shadow of its former self and had been taken over by the Zahl.
Annorax's continued attempts to restore the Imperium were witnessed by the USS Voyager when it entered Krenim space in 2374. Consequently, several different timelines were encountered.
In the 'original' timeline for Voyager, Krenim ships wandered Zahl space claiming it as their own, but lacked the military might to enforce their claim. Following the erasure of the Zahl from time, the Imperium became a huge empire spanning over 800 planets. Obrist, a senior officer on the weapon-ship, reported this as a 98% restoration of the timeline. Their vessels were much more powerful, capable of inflicting severe damage to the Intrepid-class vessel.
Following an error in a temporal incursion, the Krenim were reduced to a pre-warp civilisation, confined to their home system, with only a handful of small vessels.
The weapon-ship was finally destroyed by Captain Janeway and Voyager, and the original timeline was restored - the Krenim remaining in dispute with the races around them. (VOY: "Year of Hell, Part I", "Year of Hell, Part II")
- Although it is unclear who the Krenim were in dispute with in this 'restored' timeline, it seems likely that it is the Rilnar.