Forum adverts like this one are shown to any user who is not logged in. Join us by filling out a tiny 3 field form and you will get your own, free, dakka user account which gives a good range of benefits to you: No adverts like this in the forums anymore. Times and dates in your local timezone. Full tracking of what you have read so you can skip to your first unread post, easily see what has changed since you last logged in, and easily see what is new at a glance. Email notifications for threads you want to watch closely. Being a part of the oldest wargaming community on the net. If you are already a member then feel free to login now.

Chaos will always be a threat yes but to what degree? Think back to the great crusade, yes there were alien civilizations who worshipped Chaos but you could say it was barely noticeable.

The traitor legions spend so much time fighting each other and sometimes within their own armies.

Cadia. Yes csm and daemons can mass attacks elsewhere in the galaxy but most chaos forces have become warband, much smaller and loosely organized than imperial counterparts. Plus, the chaos space marines don't have as many forge worlds to manufacture ammo and vehicles. A lot of these small warbands probably don't even have access to any.

Games Workshop would never let their poster boys fall, okay that was just a joke.


I love chaos factions, they have most interesting fluff. But they seem too scattered. Even when joined forces they can't really do too much. The imperium outnumber them and chaos also has to deal with necrons and tyranids. Etc

Chaos will always be a threat, that there is no doubt because it is within everyone's mind and causes corruption. I know minority of people on other warhammer sites claim chaos will inevitably win without a doubt. What are your thoughts?

The threat of chaos isn't in its armies, its witches, or even its daemons.

The threat of chaos is that it is in normal people, every citizen of the Imperium. Chaos will win, because it will chip away at law until there is nothing left. You cannot defeat chaos, you cannot obliterate it. Even if you eliminate every chaos worshipper alive, more will simply appear.

 Furyou Miko wrote:
The threat of chaos isn't in its armies, its witches, or even its daemons.

The threat of chaos is that it is in normal people, every citizen of the Imperium. Chaos will win, because it will chip away at law until there is nothing left. You cannot defeat chaos, you cannot obliterate it. Even if you eliminate every chaos worshipper alive, more will simply appear.

Unless you wipe out all life in the galaxy, which is what the Tyranids threaten to do. If the galaxy were to be sterilized, the Chaos gods would starve to death, not necessarily quickly but they would eventually.

Of all the threats, the vast majority are threatening humanity with some form of enslavement or foreign domination. Whether it be to Orks, to Dark Eldar, to the C'tan, to the Chaos gods, or Tau, humanity would still survive albeit in some oppressed or degraded fashion. The manner of survival may be repugnant to the reader but the species as a whole would still survive even if the life of any one individual is short or brutal.

However Tyranids present a different sort of threat: that of total and utter extinction for the individual and the species. That is where their horror lies: they don't care about you. You are not even a plaything or slave to them. Other races and factions care enough to hate and oppose your ideals, or look down on you as primitive and barbaric or effete and wimpy. The Tyranids are like an implacable and uncaring force of nature, and puts individuals of all races in their place as insignificant specks in a hostile but most of all uncaring universe, to be swept away in an avalanche of claws and teeth.

Whoops... there doesn't seem to be anything here.

Chaos is more of a philisophical and spiritual threat than the other threats assailing the cosmos. For the imperium it represents a darker reflection of itself. It encompasses everything that is wicked about mankind. And it is subtle. No other threat nearly strangled the imperium at birth like chaos nearly did. Some of the imperium's greatest sons and daughters have turned to the dark powers, including some of the men who helped build the imperium. It is also a threat that will be around as long as sentient life is. The imperium could triumph over every other faction and be the only power left and they still wouldn't be rid of chaos. Even if its not the traitors in the eye or maelsrom, chaos will find a foot hold elsewhere in the imperium to plague it.

Enough of a threat that the Imperium has spent ten thousand years combatting it on all levels, just to contain it.

I don't know about hypothetical Imperium-destroying endgames, but in terms of the setting as it stands now Chaos has done more to shape and impact the Imperium than any of the alien races.

Remember your average Imperial Citizen doesn't know anything about the heresy, the warp, daemons, or the Chaos Gods. Not a single thing.

Chaos is dangerous because a planet's very knowledge of it will cause everyone to go chaos and will require a large outside army to reclaim control of the planet.

 Furyou Miko wrote:
The threat of chaos isn't in its armies, its witches, or even its daemons.

The threat of chaos is that it is in normal people, every citizen of the Imperium. Chaos will win, because it will chip away at law until there is nothing left. You cannot defeat chaos, you cannot obliterate it. Even if you eliminate every chaos worshipper alive, more will simply appear.

Unless the nids when. Cant really have any chaos worshipers when there are no living things in the galaxy.

Because they can't be beat. You burn out one cult, 2 more take its place. You save one world from a chaos invasion, 2 more fall. You kill a chaos Champion, a stronger one rises to command. You kill off a daemon only for him to appear again. It's simply that Chaos has infinite numbers. Even the Tyranids have limits and we don't actually know how many their are.

Remember, Chaos already annihilated a previous great galaxy spanning empire in 40k's past: the Eldar. During this time, Chaos also helped contribute to the downfall of mankind by making Warp travel nearly impossible. The reason that humanity (and other races) survived and recovered is because Chaos doesn't want a dead universe. Chaos needs mortals (which is why races such as the Tyranids or the old school Necrons would be Chaos's greatest threat). But what happened when humanity recovered? They started a huge Imperium that causes misery, despair, and repression, thus fueling the dark Gods like never before. Arguably, the Gods WANTED the Imperium to turn out the way it is. That's why Chaos didn't become a big opposing threat until later in the Great Crusades. The nearly identical nature of Horus's Chaos inspired vision and the actual 40k present confirms this.

In short, Chaos is a very different threat from the "BLAARGH, KILL EVERYTHING" of some xenos, but it is still a very serious threat because the servants of Chaos are capable of far greater subtlety and manipulation. Chaos may also be humanity's best hope of actually defeating races like the Necrons, Tyranids, and Orks, because the dark Gods can use their Warp juice in ways that help offset those races technological or numerical advantages.

Imagine how scary the universe would become for everyone else if all of humanity actually managed to unite under the banner of Chaos undivided. But the biggest thing that undermines the Chaos threat is that Chaos, unlike say, the Hive Mind, isn't a force that unites very well. In that way, Chaos is like the Orks: could wipe out everything, if they could just get their act together.

Also, the ultimate threat to the galaxy is whichever army's codex you happen to be reading at the time.

Iracundus wrote:

 Furyou Miko wrote:
The threat of chaos isn't in its armies, its witches, or even its daemons.

The threat of chaos is that it is in normal people, every citizen of the Imperium. Chaos will win, because it will chip away at law until there is nothing left. You cannot defeat chaos, you cannot obliterate it. Even if you eliminate every chaos worshipper alive, more will simply appear.

Unless you wipe out all life in the galaxy, which is what the Tyranids threaten to do. If the galaxy were to be sterilized, the Chaos gods would starve to death, not necessarily quickly but they would eventually.

Of all the threats, the vast majority are threatening humanity with some form of enslavement or foreign domination. Whether it be to Orks, to Dark Eldar, to the C'tan, to the Chaos gods, or Tau, humanity would still survive albeit in some oppressed or degraded fashion. The manner of survival may be repugnant to the reader but the species as a whole would still survive even if the life of any one individual is short or brutal.

However Tyranids present a different sort of threat: that of total and utter extinction for the individual and the species. That is where their horror lies: they don't care about you. You are not even a plaything or slave to them. Other races and factions care enough to hate and oppose your ideals, or look down on you as primitive and barbaric or effete and wimpy. The Tyranids are like an implacable and uncaring force of nature, and puts individuals of all races in their place as insignificant specks in a hostile but most of all uncaring universe, to be swept away in an avalanche of claws and teeth.

That's why I'd be curious to see what happens in case of a MASSIVE Tyranids invasion.

I'm sure Chaos would side, even if indirectly, with the other races. If the Tyranids numbers waiting outside the universe were as big as feared they could probably be THE race to put an endgame.

Chaos is the largest most immediate threat to the IoM.

The nids are far away and slow. Orks take time to grow and are disorgonized. Eldar are too weak. Most of the crons are just waking up and they are slow. Tau lack numbers.

Any other enemy can win a thousand major battles and the IoM will still stand. Any other enemy will have to consolidate their gains after winning a few battles.


Chaos on the other hand is very different. If Chaos wins a few battles, more traitors will turn to their cause. Their ranks will swell and they could sweep through the galaxy like a whirlwind. no consolidation, no waiting for resupply, just attack after attack, each victory giving Chaos new legions of men and material to deploy.

Civil wars are like that, people want to be on the winning side. Take a look at the CCP vs KMT in China for an example. Once the communists started winning battles in the open field, it was over in a few months, as half the KMT army turned traitor.

Chaos's threat is insidious. The corruption is far more dangerous than its armies.

The remnants of the Traitor Legions haven't made any significant gains in ten thousand years, and their victories are measured in planets, in a galaxy of hundreds of thousands, if not more, settled worlds.

The tabletop gives an inordinate amount of attention to the "armies" of Chaos, but that's because it's a wargame. The reality of the universe is that the military forces of Chaos are actually fairly impotent, and rely on sneak attacks, and raids, rather than sustained campaigns. They've tried and failed twelve times to conquer the galaxy and each time it takes them hundreds, sometimes over a thousand, years to recover militarily.

The Tyranids have conquered more Imperial space in 360 years than Chaos has in 10,000. The Orks have conquered more space. Probably the Necrons too.

Where Chaos becomes a danger is in its corruptive influence among the populace of the Imperium. It's why the Inquisition is so vigilant and ruthless. The Traitor Marines themselves are just the bitter, disorganized remnants of the once-proud Legions, mostly made up of substandard replacements and led by raving, delusional psychopaths.

 Judge Dredd wrote:

I'm sure Chaos would side, even if indirectly, with the other races. If the Tyranids numbers waiting outside the universe were as big as feared they could probably be THE race to put an endgame.

Pretty much. Tyrannids will have trouble taking over the galaxy because odds are the entire galaxy would unite against them (or at least stop fighting each other so they could focus ont he Tyrannids separately) if they ever became that big a threat. There's already at least one fluff incident where Chaos marines and Space Marines called a cease fire when Tyrannids arrived, although the two factions separated rather than teamed up to fight the tyrannids.

....really, there's a reason why Tyrannids have NO ONE on the allies matrix.

Chaos is the greatest threat because it can unravel reality itself

 Furyou Miko wrote:
The threat of chaos isn't in its armies, its witches, or even its daemons.

The threat of chaos is that it is in normal people, every citizen of the Imperium. Chaos will win, because it will chip away at law until there is nothing left. You cannot defeat chaos, you cannot obliterate it. Even if you eliminate every chaos worshipper alive, more will simply appear.

Negative Ghost Rider, the irony of Chaos is just that, it needs the Imperium as much as the Imperium needs the warp. It's why a lot of Inquisitors like Eisenhorn protect the status quo instead of having the idea of wiping Chaos out as well as that being an impossible task. If Chaos were to win, then it would see the prophecy foretold to the Alpha Legion where Chaos would consume itself and thus destroy itself. To me the most ironic thing is that a balance must be kept for both to exist. If this balance it tipped significantly then it is mutual destruction of both sides. There are only two factions who would thus benefit from this: Tyranids to consume what is left or the Necrons to have finally destroyed the denizens of the warp to secure the galaxy for themselves.

The warp and thus Chaos are the culmination of the emotions of warp connected species, it's how the Chaos gods exist, Gork and Mork rage their eternal battle, how the Eldar had an extended panatheon of gods and goddesses and how we saw the rise of the Emperor into a god. These species need the warp in order to survive. The Eldar recognized that Chaos was needed to balance things but when they lost their focus, and embraced a hedonistic lifestyle, boom you birth a new god so now they strive even harder to keep this balance.

Chaos uses these species like a battery and to corrupt them all would eventually lead to destruction of themselves so they need the Eldar, the Inquisition, the Grey Knights, Space Marines and other forces of "order" to keep them reigned in whether they like it or not, same as these forces need to see that a little bit of Chaos is needed for the survival of all warp based species.

That is the grand irony of this entire setting.

Animus wrote:
Chaos is the greatest threat because it can unravel reality itself

Chaos cannot unravel reality with reality helping, aka Chaos Worshipers sacrificing a psyker to open a portal to the Warp. Should reality no longer be able to help, (IE nids or Necrons destroy em all) then not only would chaos be unable to even effect reality but also cease exisiting.

 Exergy wrote:
Any other enemy can win a thousand major battles and the IoM will still stand. Any other enemy will have to consolidate their gains after winning a few battles.

Ah, very good point. If the orks take over a planet they put orks there and make it their home. 100,000 orks can only be stretched over so many planets.

Chaos, though, is like a dam of water where a hole will endlessly pour out traitors, heresy, and daemons into the galaxy. Chaos can take root anywhere because it has unlimited numbers and power on just the other side if only the door can have a foot stuck in it to keep it open!

 changerofways wrote:

 Exergy wrote:
Any other enemy can win a thousand major battles and the IoM will still stand. Any other enemy will have to consolidate their gains after winning a few battles.

Ah, very good point. If the orks take over a planet they put orks there and make it their home. 100,000 orks can only be stretched over so many planets.

Chaos, though, is like a dam of water where a hole will endlessly pour out traitors, heresy, and daemons into the galaxy. Chaos can take root anywhere because it has unlimited numbers and power on just the other side if only the door can have a foot stuck in it to keep it open!

Unless the Necrons come along with their warp sealing technology and say "No!". Honestly, the best strategy for the Imperium? Do an Eldar and lead the Necrons to Cadia, "let them have Cadia" and then they would properly activate the pylons thus sealing the biggest tear in reality.

 Envihon wrote:

 Furyou Miko wrote:
The threat of chaos isn't in its armies, its witches, or even its daemons.

The threat of chaos is that it is in normal people, every citizen of the Imperium. Chaos will win, because it will chip away at law until there is nothing left. You cannot defeat chaos, you cannot obliterate it. Even if you eliminate every chaos worshipper alive, more will simply appear.

Negative Ghost Rider, the irony of Chaos is just that, it needs the Imperium as much as the Imperium needs the warp. It's why a lot of Inquisitors like Eisenhorn protect the status quo instead of having the idea of wiping Chaos out as well as that being an impossible task. If Chaos were to win, then it would see the prophecy foretold to the Alpha Legion where Chaos would consume itself and thus destroy itself. To me the most ironic thing is that a balance must be kept for both to exist. If this balance it tipped significantly then it is mutual destruction of both sides. There are only two factions who would thus benefit from this: Tyranids to consume what is left or the Necrons to have finally destroyed the denizens of the warp to secure the galaxy for themselves.

The warp and thus Chaos are the culmination of the emotions of warp connected species, it's how the Chaos gods exist, Gork and Mork rage their eternal battle, how the Eldar had an extended panatheon of gods and goddesses and how we saw the rise of the Emperor into a god. These species need the warp in order to survive. The Eldar recognized that Chaos was needed to balance things but when they lost their focus, and embraced a hedonistic lifestyle, boom you birth a new god so now they strive even harder to keep this balance.

Chaos uses these species like a battery and to corrupt them all would eventually lead to destruction of themselves so they need the Eldar, the Inquisition, the Grey Knights, Space Marines and other forces of "order" to keep them reigned in whether they like it or not, same as these forces need to see that a little bit of Chaos is needed for the survival of all warp based species.

That is the grand irony of this entire setting.

That's a big negative. If Chaos wins it will no longer consume itself or we have no reason to believe so. It was Horus that would make that happen due to the inner turmoil he would feel when he achieved his goals and saw the consequences. The Kabals,(#1's) prophecy was shattered and is no longer a possible future because Horus is dead. The stagnation they dreaded has become a reality.

The war between Order and Chaos, on a metaphysical level, in order to create Balance, which is the state in which Life may flourish, goes back to Michael Moorcock's Eternal Champion series (Elric, Hawkmoon, etc).

This is also where GW drew it's inspiration for Chaos, from whence it adopted the eight-rayed star as its symbol, and "borrowed" most of its aesthetics. That GW has (in the simplification of the story concepts over time) drifted away from this terrible truth (that Order is just as bad as Chaos, but the war between them cannot ever be allowed to end) should be no surprise.

Other authors have touched on this concept in similar ways, perhaps most notably Clive Barker in "The Great and Secret Show", which serves well to illustrate the reasons behind the conflicts, and why the situation must never be allowed to change.

 Psienesis wrote:
The war between Order and Chaos, on a metaphysical level, in order to create Balance, which is the state in which Life may flourish, goes back to Michael Moorcock's Eternal Champion series (Elric, Hawkmoon, etc).

This is also where GW drew it's inspiration for Chaos, from whence it adopted the eight-rayed star as its symbol, and "borrowed" most of its aesthetics. That GW has (in the simplification of the story concepts over time) drifted away from this terrible truth (that Order is just as bad as Chaos, but the war between them cannot ever be allowed to end) should be no surprise.

Other authors have touched on this concept in similar ways, perhaps most notably Clive Barker in "The Great and Secret Show", which serves well to illustrate the reasons behind the conflicts, and why the situation must never be allowed to change.

And as usual, Psienesis comes to say it better and clarify. Aren't the factions of Order and Chaos more defined in Warhammer Fantasy than 40k? But this eternal war between Order and Chaos is the perfect setting for something like 40k because it allows for a prolonged conflict and the stagnant situation the state that the Galaxy is in, if one really thinks about it, should any one major force "win" Warhammer 40k would be a less interesting setting and the whole "In the grim, dark future there is only war" looses it's entire value.

It seems, logically, that chaos is quite easy to overcome, with a small enough level of humans. Either you could master your emotions and actions sufficiently, simply breed in the pariah gene, or any number of other methods. Mass brainwashing can help limit chaos' effect, as well, one would imagine.

The problem is that humans and other life forms are so widespread. That's why it is a real threat. But overall it seems like something that could be overcome. The problem is the logistics are nigh impossible. For that reason, it's probably the hardest threat to deal with. Unlike the enemies from outside, it's likely impossible that all life forms would be willing to come together and work to annihilate the causes of chaos.

A lot of good said here.

What little I'd add would be this. The first thing that's a special threat from chaos is that it's random. You can see the tyranid fleet coming from a segmentum away. You can track the progress of an ork WAAAUGH and divert the right amount of resources to the right place at the right time. With the exception of dark eldar (and to a lesser extent their light-side kin), everyone else is understandable, quantifiable, and predictable.

Chaos isn't. A random world over there will just suddenly cease to exist as its citizens break out in heresy and pray their planet into the warp. Another world somewhere completely different will suddenly murder itself, and then somewhere else, a cult of psykers will take over and redirect an entire imperial fleet into a warp storm.

There's no way that you can use military means to fight it, no way you can plan for it, nothing you can do but desperately try and hope you can make the individual cases better before it's too late. Chaos is like antibiotic-resistant superbugs: Everything looks fine on the surface, but then, out of nowhere, everything goes to hell and you have no other option but damage control. It's a constant, growing drain on the Imperium, and the one force that the Imperium's "war is the answer" isn't actually an answer for.

Which is especially troubling as the number of mutant human psykers continues to explode over time...

The second main threat from chaos is, as mentioned, that it's the only threat from within. This means that no amount of proverbial armor can shield the Imperium from it, and it's capable of attacking deep into the heart of everything.

Chaos, for example, is the only faction that is capable of corrupting space marines. Of taking the Imperium's finest weapon and turning it against itself, after making it even stronger than it was before. Only chaos is capable of corrupting imperial officials and getting them to flip whole sub-sectors over to heresy, or to direct a dozen chapters of space marines right into an ambush (the abyssal crusade is a particularly gruesome example of how chaos can take down vast swaths of the Imperium's army with scarce even firing a shot).

And you combine these two, and you see the threat of chaos. As fallinq said, chaos isn't about moving armies around on the map and destroying stuff. It does that too, of course, but it's threat extends far beyond the straightforward and purely military.

The warp will crush your fragile little minds. o_O

 Ciciro wrote:

 Furyou Miko wrote:
The threat of chaos isn't in its armies, its witches, or even its daemons.

The threat of chaos is that it is in normal people, every citizen of the Imperium. Chaos will win, because it will chip away at law until there is nothing left. You cannot defeat chaos, you cannot obliterate it. Even if you eliminate every chaos worshipper alive, more will simply appear.

Unless the nids when. Cant really have any chaos worshipers when there are no living things in the galaxy.

They won't. What will crush the 'Nids is a splinter-Fleet encountering a Daemon World, where the fleet's Shadow is insufficient to quell the daemons' ability to move through the Warp. Then, you get daemonically-possessed Tyranids (you think you need a soul to be possessed? You do not.) which then feeds back to the Hive Ships, corrupting *them*, and then it introduces a new concept to the collective Hive Mind of all Tyranids: Madness.

The Hive Fleets will turn on each other, desperate to eradicate this entirely new, and utterly terrifying, infection growing amongst its bio-forms: Sentience. And with Sentience comes Choice, and with Choice comes Chaos.

 Ailaros wrote:
A lot of good said here.

What little I'd add would be this. The first thing that's a special threat from chaos is that it's random. You can see the tyranid fleet coming from a segmentum away. You can track the progress of an ork WAAAUGH and divert the right amount of resources to the right place at the right time. With the exception of dark eldar (and to a lesser extent their light-side kin), everyone else is understandable, quantifiable, and predictable.

Chaos isn't. A random world over there will just suddenly cease to exist as its citizens break out in heresy and pray their planet into the warp. Another world somewhere completely different will suddenly murder itself, and then somewhere else, a cult of psykers will take over and redirect an entire imperial fleet into a warp storm.

There's no way that you can use military means to fight it, no way you can plan for it, nothing you can do but desperately try and hope you can make the individual cases better before it's too late. Chaos is like antibiotic-resistant superbugs: Everything looks fine on the surface, but then, out of nowhere, everything goes to hell and you have no other option but damage control. It's a constant, growing drain on the Imperium, and the one force that the Imperium's "war is the answer" isn't actually an answer for.

Which is especially troubling as the number of mutant human psykers continues to explode over time...

The second main threat from chaos is, as mentioned, that it's the only threat from within. This means that no amount of proverbial armor can shield the Imperium from it, and it's capable of attacking deep into the heart of everything.

Chaos, for example, is the only faction that is capable of corrupting space marines. Of taking the Imperium's finest weapon and turning it against itself, after making it even stronger than it was before. Only chaos is capable of corrupting imperial officials and getting them to flip whole sub-sectors over to heresy, or to direct a dozen chapters of space marines right into an ambush (the abyssal crusade is a particularly gruesome example of how chaos can take down vast swaths of the Imperium's army with scarce even firing a shot).

And you combine these two, and you see the threat of chaos. As fallinq said, chaos isn't about moving armies around on the map and destroying stuff. It does that too, of course, but it's threat extends far beyond the straightforward and purely military.

Yes, to your first point and very yes to the second.
I like how you worded my idea. That Chaos can turn the very finest weapons of the IoM against it.

 Psienesis wrote:

 Ciciro wrote:

 Furyou Miko wrote:
The threat of chaos isn't in its armies, its witches, or even its daemons.

The threat of chaos is that it is in normal people, every citizen of the Imperium. Chaos will win, because it will chip away at law until there is nothing left. You cannot defeat chaos, you cannot obliterate it. Even if you eliminate every chaos worshipper alive, more will simply appear.

Unless the nids when. Cant really have any chaos worshipers when there are no living things in the galaxy.

They won't. What will crush the 'Nids is a splinter-Fleet encountering a Daemon World, where the fleet's Shadow is insufficient to quell the daemons' ability to move through the Warp. Then, you get daemonically-possessed Tyranids (you think you need a soul to be possessed? You do not.) which then feeds back to the Hive Ships, corrupting *them*, and then it introduces a new concept to the collective Hive Mind of all Tyranids: Madness.

The Hive Fleets will turn on each other, desperate to eradicate this entirely new, and utterly terrifying, infection growing amongst its bio-forms: Sentience. And with Sentience comes Choice, and with Choice comes Chaos.

So is a Machine Spirit a form of soul or an allegory for computer systems? And why can't daemons infect Necrons? Is it because you may not need a soul but you need a connection to the warp?

 Ailaros wrote:
.

Chaos, for example, is the only faction that is capable of corrupting space marines. Of taking the Imperium's finest weapon and turning it against itself, after making it even stronger than it was before. Only chaos is capable of corrupting imperial officials and getting them to flip whole sub-sectors over to heresy, or to direct a dozen chapters of space marines right into an ambush (the abyssal crusade is a particularly gruesome example of how chaos can take down vast swaths of the Imperium's army with scarce even firing a shot).

There are a few minor Xenos with no codex that can corrupt space marines (like the cellkin). It's a bit rarer than Chaos though and they're... well, minor, relatively speaking. Generally no where near as effective in terms of scale, either.

So is a Machine Spirit a form of soul or an allegory for computer systems? And why can't daemons infect Necrons? Is it because you may not need a soul but you need a connection to the warp?

There is nothing saying that a Necron cannot be possessed by a Daemon. The Tomb Complexes, however, are absolutely covered in anti-Warp technologies. There is a good reason for that.

It is noted, in Codex: Necrons, that all the dimension-hopping and hyper-phasic technologies of the Necrons are of no hindrance to daemons, who can pursue even Deathmark Assassins into the spaces between dimensions, finding these places "new flavors of reality to corrupt".