It seems a little...odd. Not that the Eldar aren't massive on prescience, but (especially if it's post the Fall, so within the last 10,000 years or so) visions of the future are usually the work of Farseers, not technological devices.

The most gifted seers can dance the threads of the future at will, and see a thousand million versions of the future, and how to arrange the threads to bring forth or deny them. Given this, what is essentially a magic 8-ball with a combination lock doesn't seem to fit. Unless there's a reason for it to be that important.

The Eldar are known to have 'blind spots' - what the Farseers call 'Shadow Points' in the future which they can't see. Unfortunately (for the Eldar) a Shadow Point is often associated with an event or person of great significance, who disrupts the future so much you can't see past the event until it is resolved. Which makes any device which could see into them very significant.

Such a device might not be of Eldar origin, even if the Eldar use it (and presumably made the 'lock', knowing how dangerous it was. There are older races at work in the galaxy, after all, and several are known to have divinatory capability (the Necrons, for example, and some of the other races in the Cabal).

This allows for a second plot hook. Until they find the next significant combination, they won't get a useful vision. But simply activating it at the last settings will signal the original owners - the ones the Eldar stole it from - that the device has surfaced again, and (roughly) where it is. They also get to 'see' the person who activates it.

And they want it back.

Thank you for the input and suggestions. Good ones! I didn't know that the fall was 'only' 10k years ago. In my mind the device is much much older but it can have easily resurfaced after the fall or being brought into use then cause of the dire need, which aligns whith your next suggestion that it's not theirs... originally.

So an ancient race even for eldar standards... I can only come up with C'tan, Necrons and Yu'vath and of course Anyhting i can imagine, but I like to keep in touch with canon. Of these three the most obvious would be the Necrons as C'tan would be a definate TPK and yu'vath are dead, any others I'm overlooking.

Which brings me to the overall plot... What will be the next vision/epic event. And while we're talking plot, how would you imagine slaanesh and nurgle would react to this resurfacing of Isha.

Nurgle has lost his guinea pig which means very erratic diseases (not sure what that would mean). Also Isha no longer whispers the cure to these diseases into the 'world'...or does she?

Slaanesh on the other hand was after Isha after the fall and Isha sought 'refuge' at Nurgle, so now what?

Which brings questions like: what will these gods do in general and what specifically to the party? The latter can easily fold two ways: slaanesh either does not care or is positively interested in the party as his/her price is brought back into his/her reach due to the party.

Nurgle... I don't see Nurgle as a vengeful god but actually as 'Grandfather Nurgle' after all 'disease' stimulates progress and evolution (how weird that may sound). So I don't see a personal vendetta, his followers however might see this differently. But I'm open to suggestions.

In summary

1. What will be the next vision

2. Who are the original owners

3. What is the effect on the universe of Isha no longer being the guinea pig of Nurgle

4a. How does slaanesh act on the surfacing of Isha

4b and how to the party (if at all)

5a and b same as 4 but concerning Nurgle.

Necrons do have some time/space flubbery, arcane devices, and they do so without touching the warp, so a cube covered in numbers and dials, filled with spin-joints, that might have something to do with time or space-manipulation would certainly be fitting. You might have a C'Tan fragment in it, powering/directing it, and driven insane from hunger and isolation.

If you like the Eldar, they ARE a VERY ancient race, and pre the Fall, they possibly built any number of nightmarish devices. Most would say that the Eldar (Craftworld, Exodite, Corsair, and Harlequin) all actually have improved, and gotten nicer since then; the Dark Eldar are still sadist pricks far beyond salvation, but that's their problem. Ancient Eldar might've made some such device. The Dark Eldar could, too. They murder their potential psykers, and enjoy murdering Eldar Farseers, too, but I doubt they liked losing total access to the knowledge of the future, so they might've tried to twist the souls of a Farseer, or 10, and find a way to make a device see the strands, and predict what will be, but without Slaanesh finding them. Slavers and raiders, specifically, could benefit from a predicting cheat device.

So Necrons with a dash of C'tan is The most likely candidate. (Interesting post count you have! And the this remark will only have a short lived meaning... As with your next post it's lost in obscurity)

Any suggestions on my other questions, in my 2nd post?

I didn't know that the fall was 'only' 10k years ago.

Yeah. The Birth of Slaanesh was the event which blew away the warp storms which had isolated Terra, and led to the launch of the Great Crusade a few decades later.

Most of the Dark Age of Technology/Age of Strife was mankind venturing out into a galaxy which - in so far as it was dominated by anyone - was dominated by the Eldar Empire.

as C'tan would be a definate TPK

They're not exactly ones to have 'devices', either. All C'Tan 'things' are of necron manufacture, after they signed on to the war in heaven. A c'tan fragment is survivable if it's a small enough fragment, and no-one says, for that matter, that it definitely has to get out.

Hacking off the necrons isn't a great plan either, though.

Dark Eldar is a good idea, too. Possibly less lethal, and with a ready-made link to the Dark Eldar available in the Expanse (see soul-reaver)

1. What will be the next vision

What should it be? Who cares. That won't be what gets shown. See 4b below

2. Who are the original owners

I like the Dark Eldar idea.

3. What is the effect on the universe of Isha no longer being the guinea pig of Nurgle

Possibly none. This is a shard of Isha, not a complete rebirth. She hasn't necessarily escaped from Nurgle, just poked an extremity back into the real world. If she were to completely escape from nurgle.....that's a much bigger deal.

4a. How does slaanesh act on the surfacing of Isha
Depends how he becomes aware. Slaanesh doesn't want Isha for any great purpose, just as either a trophy or a snack. Expect assorted daemonic minions to be deployed to claim her.

4b and how to the party (if at all)

Unless or until they get directly involved, they're beneath his notice. Afterwards, they're in the way.

Unlike nurgle, though, he has one other option to try and manipulate the party; if the box contains one or more eldar or dark eldar souls, a bit of playing tunes on their sanity will let Slaanesh manipulate the vision shown to the party. Which means they can be shown a vision which could influence their actions, and a name for the next visionary (who they'll probably try to deliver it to) who is in fact a pawn or willing servant of the Dark Prince....

5a and b same as 4 but concerning Nurgle.
Pretty much the same.

Which means a two-way battle between two of the ruinious powers with the players stuck in the middle. Of course, they won't get to see most of the fighting because it will occur in the realm of chaos, but on those occasions an attempt is made on their ship, you may well see both sides breaching and fighting one another as much as the defenders.

stuff to ponder on... thanks!