The Necrons seeking to overcome the psychically attuned races created by the old ones, devised a method in which they would separate the material and the warp for all time, the pylons on cadia are assumedly just one of many other such installations scattered throughout the galaxy. (bear in mind the pylons were made roughly 60 million years ago)Thereby handicapping the newer psychic races and severely restricting the Old one's power, leaving the galaxy at the mercy of the C'tan.
they limit mutations, they seem to dilute all effects of the warp as far as i am aware.
source is necron codex 3rd edition.

 

The Eisenhorn series sheds some light on them. I'll toss out some quotes.

"Thet are totally inert, by any auspex measure known to our race, but many believe their presence explains the quieting of the violent warp torrents that make the Cadia Gate the single, calm, navigable route to the Ocularis Terribus."

A renegade Inquisitor is thinking of using a copy of the pylons. Do keep in mind that he is probably at least partially mad.

"The pylons of Cadia pacify the warp. By amplifying them using extreme-level psykers, they could be made into a weapon. A weapon to destroy the warp! A weapon to collapse the Eye of Terror in upon itself!"

Eisenhorn's response to it:

"He was raving, insane. What patches of truth or sane notions might lurk in his words, I had no idea. There was no way to distinguish them from his lunatic fancy. All I knew was that a pylon, psychically super-charged might do all manner of things, but its side-effects would be catastrophic. It could lay waste to the continent, the planet."

Less helpful than I hoped for, but it's something. Now to answer what I can answer about your questions.

I've heard some people posit that they were created by the Necron to limit the effects of the Warp and incursions into real space

I've personally never read anything about this, but then again I don't read too much Necron fluff. I'd put it at unlikely.

As well, do the Pylons have any effect on Warp travel in their immediate vicinity

They do, in a way. They calm the area around the Eye of Terror. I wonder if Cadia would be sucked into the Eye of Terror, if not for the pylons?

As to any other effect (increased/decreased time dilation or speeds) I do not know.

would that also impede any ship from exiting the Warp in their immediate vicinity?

Unlikely? As vessels have to make it to the Cadian system one way or another. Unless you're talking about a very close proximity like within the system?

 

would that also impede any ship from exiting the Warp in their immediate vicinity?

Probably not, as others have pointed out ships traverse the space around Cadia all the time. In close proximity to the Pylons you would also be in close proximity to the planet and I think that is likely to be the bigger issue (that's why they're constantly referring to "translation points" it's too dangerous to translate too close to the planets).

I would also guess that the Pylons, if truly designed by the Necrons, would not be limited to the area around Cadia. The Pylons were seemingly built before the Eye opened, so it is unlikely that they were built on Cadia because of it (though not impossible thanks to predictive sorcery). If they weren't built because of the Eye than there'd be no reason for them to only exist around the Eye and there could therefore be loads scattered around (maybe buried, maybe destroyed/semi-destroyed, maybe just ignored because they're not doing anything).

Although (and this is pure speculation) it is possible that the Pylons were originally built in response to the growing Eldar threat (the most psychicly powerful race the Necrons would've faced) and were therefore designed to encompass their spread. Since the Eye also sits on the center of the old Eldar Empire the Pylons would also surround it. So maybe there are other Pylons on other planets around the Eye (perhaps preventing it's spread in a more subtle manner) or perhaps they were destroyed in the birth of Slaanesh (and the ones on Cadia were a fluke in there survival).

Ultimately, it's a big galaxy if you need there to be other Pylons (or Pylon-esque devices) elsewhere than you are free to come up with whatever reason you want for them to be there.

 

Of all the BL novels out there I think this is the first time I've ever referenced a Caiphus Cain novel for fluff, but I'm fairly sure in one of his books that the Inquisitor Amberley Vail mentions the Cadian pylons when discussing Necrons and their place in the Galaxy. I also vaguely recollect something about a Mechanicus expedition studying them and linking them to the Necrons. Can't say what book it was in though.

Also, the reason all the Black Crusades seem to head for Cadia is because the pylons make it the only stable warp transit point out of the Eye in that area of the galaxy.

 

Also, the reason all the Black Crusades seem to head for Cadia is because the pylons make it the only stable warp transit point out of the Eye in that area of the galaxy.

I suppose the irony being if the Imperium really wanted to hamper the incursions of the Black Crusades into realspace, then someone needs to come up with the bright idea about how to destroy the entire planet of Cadia itself and let the Black Crusades try and work their way out of the Eye by themselves.

Aside from that observation, I'm still kinda' confused (excuse my being dense), but from the responses it would seem:
-the Pylons are psychically attuned and would therefore amplify any psykers abilities? Or is this just the ravings of a rouge/insane former Inquisitor in Eisenhorn... the book is coming back to me now.
-the Pylons acutally calm the warp around Cadia facilitating Warp travel in the area, in doing so preventing the Eye from spreading as it's just a titanic warp storm
-the Pylons limit Warp-induced mutations, which I suppose is what allowed the humans that Lorgar discovered there to be in such close proximity to the Eye for so long with only the lavender colored eyes.

On the Necron front, it's wierd that the Necrons would create something that could potentially benefit the Eldar by reducing the Primordial Destroyer's power to use the warp as a weapon, a la Warp Storms, which plague the Imperium based on the Warp Power's discretion. Unless, of course, the Pylons also inhibit development of the Webway, since it actually seems to help anyone with a Gellar-field enabled warp drive.

Oh, from The First Heretic, it pretty well demonstrates the pylons don't seem to make it harder for any Chaos cult summoning a daemon, so it's not like they prevent incursions from the Warp.

Thanks all for the posts and I really appreciate your feedback.

 

In other words, whoever holds Cadia, controls the most stable Warp/Realspace interface. Without holding Cadia, any Chaos force beyond would be cut off, isolated and without reliable re-supply. Fun.

I don't know much about the Pylons, but they sound like a variation on the Null Field Matrix, mentioned in the 5th ed Necron codex.

 

Don’t ask me to reference this as I have no clue where I heard this, but I have a vague recollection that in the original fluff they were supposedly created by the Eldar after the fall as a means of halting the growth of the eye of Terror and the spread of Chaos into the Galaxy.

Now the reasons why this is more likely than the Necrons in my opinion is why would the Eldar have left them standing so long after the disappearance of the Necrons if they limited the physic ability of their race, surly they would have taken them down.

Now it is possible that this has changed, and that the New Fluff indicates that the Necrons are now the builders of them, as we all know how GW likes to rewrite the fluff side of things, when new races... etc, come into the game

 

One thing does strike me though. If they were constructed by the Necrons, it wasn't to calm the warp around the Eye, because the Eye didn't exist when the Necrons were last an active empire. Maybe they were to combat the Eldar somehow? Not allowing them to open webway portals on planets with pylons?

 

As i previously stated, it wasn't to close a specific rift in realspace, it was simply one installation of a plan to create a barrier that would forever isolate the two realms of existence.
They were losing the war of heaven to the new psychically attuned races, their response was to try and create a way to forever negate the warps influence and thereby rob their enemies and ensure that they were permanently at the mercy of the C'tan.

 

As i previously stated, it wasn't to close a specific rift in realspace, it was simply one installation of a plan to create a barrier that would forever isolate the two realms of existence.

Whilst that may be a logical assumption, it is still nonetheless an assumption. As far as I remember there was no direct connection in the text between the brief mention of the C'tan's grand plan in Codex: Necrons 3rd edn and the Cadian pylons. As far as we know, the Cadian pylons may well have been intended to close a particular warp rift. It's unclear how the revelation of the Necron rebellion against the C'tan effects the lore surrounding the C'tan's grand plan, especially considering (as far as I am aware) it wasn't mentioned at all in Codex: Necrons 5th edn.

Regardless, despite the pylons (whether through degradation and disrepair or simple ineffectiveness) the Eye of Terror can, and actually is expanding and many pylons "buckled under the fury of the warp" during the 13th Black Crusade. Indeed, Abaddon's ultimate strategy revolves around shattering the influence of the pylons in order to expand the Eye of Terror along the Crimson Path towards Terra itself.

 

The Pylons are basically null field matrices, they separate the warp from realspace in their vicinity. The thing is, they were built millions of years ago and are in varying states of disrepair, so don't completely work. It is also unlikely that Cadia is the only world they exist on, but Cadia's proximity to the Eye of Terror has mad them much more noticeable than pylons out in the middle of nowhere. I believe the revolt against the C'tan cut this and many other Great Works short, preventing them from being completed, and the projects forgotten in the new political landscape, allowing them to fall into disrepair. If they were to be repaired however...

 

Something you guys seem to be overlooking is that the Eye of Terror is right where the center of the Eldar Empire once was. It is reasonable to conclude that the area was once an Old One power base where the Eldar consolidated after the War in Heaven. If that's the case, the Pylons being put on Cadia would have been the best place to test them, not to mention a giant "middle finger" to the Old Ones. When the Pylons were fully functional, they could have given the Necrons a big advantage in the area. The psychic races would be cut off from the Warp and at the mercy of Necron Technomancy.

As Iron Angel and myself have said, the Pylons are likely Null Field Matrices. According the fifth Ed Necron codex, a Null Field Matrix requires lots of power and proper maintenance to function. There are very few still functioning given the 65 million years of the Great Sleep. Given there is no apparent Necron presence on Cadia, we can conclude the Pylons are in disrepair and not working right.

 

What if Cadia was really a staging ground for a massive offensive against the Eldar empire? The Pylons were there to dissuade a counterattack, and keep the massing forces safe from any sort of clairvoyance the Eldar might employ to try to detect and prepare for them. The attack was then cancelled due to the Rebellion and the Pylons forgotten by the power-hungry nobles who would rather devote resources to their own campaign than funnel resources into a project that didn't directly benefit them?

 

I think the pylons weren't meant for the Eldar. The Necrons were winning big time once they managed to infiltrate the Webway.

Maybe the pylons were in fact intended for the rise of Chaos. Perhaps it was foreseen that once the Necrons awakened from their mass hibernation, a period of dormancy to give the races savaged by the Enslaver plague time to reestablish themselves, the Chaos powers would become the galaxy's most potent enemy.

 

We have seen one example where one of the pantheon has fully taken over a part of the galaxy and all that was left was a wasteland of ash and ruins (Aurelian).

If Abaddon accomplishes this, wouldn't the same thing happen to Terra and all of humanity's domain thus leaving nothing for the pantheon to feast on?

 

You mean Slaanesh and the Eye right? If so, the reason for that (as Ingethel claimed anyway) was because the Eldar, at the moment of their ascension, suddenly and utterly rejected the god that they had birthed.

Abaddon's goal is - and has been for several editions - to establish an "empire of Chaos" over the ashes of the Imperium. If we couple that with the lore (cited in at least three sources) which claims that if the Emperor falls then the immaterium will consume the materium, then he might well achieve his goal if he manages to establish the "Crimson Path". If such a thing occurs it might no longer be a matter of food-sources, emotion, and sustenance, all will be immaterial.

 

How about the regions beyond the Astrominican's guiding light? The other galaxies?

Would they be assimilated into the Warp as well or are the pantheon only concerned with humanity's domain?

Obviously there is no real answer to the above but your opinion would be nice.

 

Who knows. But what has always seemed attractive to me is the idea that the warp - not the materium - is actually the centre of (un)reality. Something which is (relatively) supported by the Well of Eternity myth. We are really getting into the unascertained realm of the arcane here, but it's food for thought.

If so, the warp mirrors (or is mirrored by) all reality, not just the Milky Way. The Tyranids being an extra-galactic species, whilst relying on the warp for the functionality of the Hive Mind, suggests the warp isn't restricted to the one galaxy. Personally - minimal evidence aside - I find the notion of the warp being restricted to a single galaxy fairly absurd anyway.

If Chaos wins and conquerors/destroys everything, surely there is nothing to generate psychic consciousness in the warp and therefore now Chaos. It just goes back to what it was when the Old Ones were about.

I'm pretty sure this has been covered by The Cabal.

And what was Chaos during the War in Heaven? Well, the gods have always existed, always will, and yet have never existed.

If the materium is submerged into the immaterium, surely this incomprehensible logic will continue to apply - only then, across all reality.