I'm in the early stages of developing a DH scenario that I can 'drop in' to fill a gap in my campaign. I've hit a bit of a wall, and I'm hoping that someone out there can suggest a solution:
Basically, a daemonic entity has been bound to a planet at some point in the distant past, charged with 'terraforming' the world in anticipation of future settlement by the daemon's masters (not sure if I'll go with the Yu'Vath or something older...). At some point in the past, the Eldar (before they turned their back on 'Dread Calix' entirely) discovered this entity, plugging away at making the planet fertile. Considering this an abomination, the Eldar trapped the daemon in a psychically charged prison, capped with a stone obelisk.
Thousands of years later, the Imperium has discovered the planet and converted it into an Agriworld. With steadily increasing tithe-rates, the farmers working on the world have been forced to clear increasing amounts of land for agriculture. One of these farmers attached his tractor to a big stone with what looks like some kind of carved symbols (the eroded remains of the Eldar obelisk) and... Well, if you've ever seen a horror movie before, you know where I'm going with this (-and bonus points if you figured out that this scenario is inspired by the Clive Barker short story Rawhead Rex ).
When unleashed, the daemon, which has forgotten its origins and come to believe that it is an actual nature deity (a daemon forgetting who/what it is is a plot device taken from the Black Library Daemonhunter novel Dark Adeptus ), kills the local farmers who won't worship him, leaving only their children (yes, as in - Of The Corn !) working in the fields and naively revering the entity they call The Reaper Man ("He makes things grow up... and them he cuts them all down..."). And the daemon's influence is slowly spreading beyond the initial community where he was unleashed...
I'm kind of basing the daemon's abilities on the Alan Moore-era Swamp Thing ; it can grow new bodies from live plants; 'teleport' between plants; form multiple bodies (we use minis in my campaign, and I just picked up a box of plastic Warhammer Dryads); even create a giant body if needed (I have an old Fenbeast figure from the Warhammer summer campaign 'Dark Shadows', from back when GW held special worldwide campaign events every summer...).
I want to make it clear that physical force won't win the day- otherwise, the Eldar would have simply killed the daemon and been done with it. The issue I'm having is, how can the PCs overcome something like this? The only thing I'm coming up with is the cliche'd 'It's vulnerable to this magic rock (or whatever)!" I guess I can go with that (it's how Rawhead Rex ends, after all), but I'm hoping to use something more clever than that- ideally something that operates within the existing DH rules, if possible.
Any suggestions...?