Just a few stubs of ideas for future campaigns - would be nice to gather a bunch of these...

High Combat

A Hive Fleet arrives at the edge of the Koronus Expanse - presaged by omens, reports of the shadow in the warp, trouble with genestealers on established worlds, fleeing unknown xenos ships from beyond and sightings of the tyranid obsessed Inquisitor from the Calixis Ordo Xenos.

Deathwatch units might be sent from the Jericho Reach in an odd twist, local Marine chapters may be rapidly mobilised, as the enemy becomes known even rival/warring Rogue Trader houses may be forced into unlikely alliances to defend.

Potentially this can be played as a series of sector defence / fleet battles or on a smaller scale recovering essential materials/ sacred artifacts / people from a world under attack.

In general its probably not a great sector for Tyranids to attack - too many dead worlds and some with unwholesome threats even tyranids probably ought to avoid like Yuvath worlds and the weirder stuff - a heavily depleted hive fleet may well founder in the sector if opposed in an organised way.

One thing that could shake up a campaign

Supposing the RT dynasty finds out ahead of time: there is a big warpstorm that closes the Koronus Passage for months, even years - Perhaps it's an offshoot from the Screaming Vortex - All charted routes are impassible; nobody can get in or out; isolated colonies are threatened; chaos and xenos activity increased. Kind of like what happened to the Gothic Sector.

The dynasty must either find a way around the storms back to key Imperial markets, or find a reason behind the Maw closing shut.

On the Imperial side, other rogue traders and invested merchants are suddenly ruined when assets become locked behind the warpstorm. Trade is at a standstill, so Acquisition can get more difficult as stockpiles diminish. This may overstretch their Profit Factor too, but it's an opportunity to bring on new endeavors to reverse that misfortune.

When and if the storm subsides, things don't have to go back the way they were. This could mark a turning point in a campaign. A rough stretch may be all they need to change direction.

That is, if the GM is not happy with the direction