So first of all I should say *SPOILERS* for the Ark of Lost Souls scenario and for any Mortis Thule mission
I'm currently coming to the end of running the Ark of Lost Souls scenario(s) and the Kill-Team will soon be escaping onto the surface of Karlack. I'm sure one of the PCs are going to want to return to Mortis Thule to complete one of the optional missions that they couldn't get to (the enslavers). This is because I seeded it with loads of stuff that would be interesting for his character (a lost member of his chapter with a rosarius from his parent chapter, potentially near by).
It would be just a bit boring for me to simply run that on it's own. By the time I get them back to this mission they will be rank 5 or 6, so I'll be wanting them to achieve something epic. The vague plan will be for them to be intercepted by an Eldar farseer that they met before, who will task them with going to the centre of Mortis Thule and disabling it. Of course I'll have to do something to ensure they don't simply kill the farseer, as they just might do, but that's outside the topic for this thread.
The Ark of Lost Souls book implies that in the centre of Mortis Thule is a Necron artefact that is creating the black rock substance of the space hulk. It doesn't however, give any notes on what it would look like, what size it is or any form of scale.
So my main questions are:
1/ Is there official information on what is at the centre of Mortis Thule anywhere outside the "Ark of Lost Souls" book?
2/ Has anyone else had PCs journey to the centre of Mortis Thule in their games? If so what did they find there?
3/ I always appreciate general suggestions. Anyone have any?