To the contrary, there are three Warhammer 40k RPGs that take place in sectors that have recently been brought under the control of the empire or are currently being taken over:
- Calixis Sector is the setting of the Dark Heresy RPG
- Koronus Expanse is the setting of the Rogue Trader RPG
- Jericho Reach is the setting of the Deathwatch RPG
Some information about the Calixis Sector:
The Calixis Sector is an Imperial sector in Segmentum Obscurus near the Halo Stars and the Eye of Terror. Conquered by Lord Militant Angevin a thousand years ago, the Calixis Sector contains many heavily populated and important worlds, though it lies a great distance from the Imperium's heartland. Its first governor was Drusus, one of Angevin’s most capable generals, a man now revered as an Imperial Saint.
From the Calixis Sector article on Lexicanum
You have a complete history of the Sector here. Some relevant dates:
- 723-736.M36 - Haarlock discovers a new region he names Calyx Expanse
- 322.M39 - Angevin Crusade to bring the Calyx Expanse into the light of the imperium begins.
- 384.M39 - Angevin Crusade officially ends, i.e. the Calyx Expanse has become the Calixis Sector
Some information about the Koronus Expanse
As is true of the Calixis Sector itself, the Expanse was untouched by the God-Emperor's Crusade many millennia ago and so it is a realm of fearsome xenos, treasures beyond imagining, heathen worlds of men, and the echoes of the ancient doom.
From the Koronus Expanse article on Lexicanum
Some relevant dates (taken from the Fandom article on the Koronus Expanse):
- 997.M40 - Discovering of the Koronus Passage, a way between two Warpstorms from the Calixis Sector to the then discovered Koronus Expanse
- 188-274.M41 - Winterscales Realm is built
There is even a part of the Imperial Navy in the Koronus Expanse, dubbed Battlefleet Koronus.
Battlefleet Koronus, officially known as Passage Watch 27-Est, is a small fleet of Imperial Navy vessels charged with the protection of the Koronus Expanse, a dangerous unexplored region of the Halo Stars located beyond the Calixis Sector in the Segmentum Obscurus, which lies on the northern edge of the known galaxy.
From the Battlefleet Koronus article on Fandom
Information about the Jericho Reach:
Currently a bastion of Chaos, several other threats have also set their eyes on the Reach. The Tyranid Hive Fleet Dagon is encroaching into the region from the north-east. In the south, the Tau have colonised several worlds. Since 777.M41 the Imperium has been pursuing the Achilus Crusade, also known as the "Dead Crusade". The troops and fleets involved in the Crusade are from the Segmentum Obscurus and use a warp gate to travel to the area, which would otherwise take years of travel in the Warp to surmount any decent offensive.
The Jericho Reach was once called the Jericho Sector, before years of neglect by the Imperium left the sector to fall into decay and eventually into the hands of Chaos. For thousands of years, Chaos has been left to fester in the once rich Imperial worlds, observed only by silent posts manned by the Deathwatch.
Some dates about the Jericho Reach from Fandom:
- M32 to M35 - It is the Jericho Sector
- M36 to M37 - Fall of the Jericho Sector
- 889.M36 - Fall of the _Jericho Sector, it becomes the Jericho Reach
- 777.M41 to Present - Achilus Crusade to reclaim the Jericho Reach into the imperium once again
If you want more information, check the Crusades that have taken place