A good way to combine the games together would be to have a story arc where the Achilus Crusade ends, and the crusader forces are recalled back through the warp gate which got them there. It is possible for the Imperium to win, lets say that a victory happens in one front which starts a chain reaction through other fronts which then lead to a victory (or defeat) of imperial forces.

Upon arrival through the warp gate, it would surely come to the attention of some military commanders that the Kronus expanse is virgin territory just waiting to be conquered by the Imperium. The creation of a Koronus Sector might be on the agenda of some leaders, especially those of Calixis sector which see Saint Drusis as wanting them to conquer the expanse anyway. Many Rogue traders would have maped out the area and have a good idea of the planets which inhabit it.

The tone of the war would change. Prior to this, it would be rogue traders acting as conqistadores. Now, the Space Marines and Imperial Guard (and Sisters of Battle) can be brought into the fold. The Storm wardens have their homeworld in the Calixis sector and would naturally see the Expanse as their stomping ground worthy of a crusade (after all, assuming the Achilus Crusade is finished what else are they going to do?). No doubt the Storm Wardens could probably commit a few companies towards the effort, which would be an extremely powerful fighting force.

Rather than the 3 fronts in the Achilus Crusade, there would be about 6 "fronts". 1/ stopping the Ork Waaagh growing, probably the largest front, 2/ skirmishing with the Eldar of Craftworld Kaledor 3/ stopping Rak'Gol expansion 4/ fighting the Styxx, 5/ Fighting the Kroot (which they would have done fighting the Tao anyways 6/ fighting Chaos Reavers

The scale would be different, probably not as intense as it was in the Achilus Crusade. The Orks are disorganized and not the monolithic enemy the Tyrannids are, Eldar break easy, and there seems to be all of 1 Chaos marine leading Chaos forces (as opposed to whole armies of them in the Deathwatch setting). The Deathwatch might even decide to create a small watch station in the Koronus expanse to monitor Xenos activity and further Imperial expansion in to the region.

One more thing... it allows Fantasy flight a legitimate reason to have Space Marine Strike Cruisers sail through the Expanse, fodder for a new expansion.

peterstepon said:

Well... let's see, stopping an Ork Waaagh is a challenge in its own right - they're difficult to stop once they've started by any stretch of the imagination.

Technically, Kaelor isn't in the Koronus Expanse - it passes through the Calixis Sector once a millennium, certainly, but if you look at the Eldar activity in the Expanse, they're definitely there for something. And that something is terrible indeed...

The Rak'Gol and the Stryxis are unlikely to stand up to a Crusade force, true (though the Stryxis will probably try and sell the Crusaders something first, before going into hiding), but they're not really the issue.

Fighting the Kroot... Kroot don't always regard themselves as citizens of the Tau Empire, so there's no guarantee that winning the Achilus Crusade and driving back the Tau will put an end to Kroot movement through the Koronus Expanse.

Chaos Reavers... there's more than one group of them floating around the Expanse for a start, ranging from the Saynay Clan's sorcerers, to the cruel Reavers of Karrad Vall (not a Chaos Marine... and hardly a pushover), to independents wandering the Expanse for plunder and slaves. And the thing is, Karrad Vall is looking for something too... he's not just in the Koronus Expanse to plunder, pillage and enslave. And that's before you consider that there's a colossal nest of Chaos Worshippers lurking within the Screaming Vortex at the Coreward Edge of the Expanse (the Screaming Vortex is, afterall, the setting for Black Crusade).

And you've managed to overlook the other threats - the ghosts and ancient war-constructs of the Yu'Vath, the horrors that saw the Egerian Collective rendered extinct, and the malefic light of the Rifts of Hecaton.

In the years it'll take to secure victory over the Jericho Reach (and it will take years at best), the threats and perils of the foul and haunted Koronus Expanse will only grow in magnitude - the WAAAGH may have started, the Eldar and/or Karrad Vall may have found what they were looking for, and the haunted and unholy nature of the Expanse will only grow.

Such an undertaking will not be an easy one, and it is far from the array of physical threats that comprise the visible portion of the Jericho Reach/Achilus Crusade setting...