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Also, I think it's less that the Tau have a small Warp signature and more that they actually are essentially very mild Blanks. This would explain why they can't be Warped while inanimate objects (which have no Warp signature whatsoever) can with ease.

But they can be. They can definitely receive the benefits of Warp-based "technologies" (is why Farsight is still alive), which implies that they are likewise subject to the corrupting effects of Chaos. If, say, a Tzeentchian Sorcerer were to blast a Fire Warrior with a Bolt of Change, you'd expect that Fire Warrior to sprout tentacles and beaks and otherwise collapse in a screaming, mewling pile of rapidly-mutating flesh.

 Psienesis wrote:

The Tau have the best infantry rifle in the galaxy. The standard-issue Tau weapon is blatantly superior to the weapon of the Imperium's elite warrior class. In no way does a bolter compare favorably to a pulse rifle whatsoever. The Necrons and Eldar both are incapable of producing an infantry gun that hits as hard as a pulse rifle, or one capable of hitting at such a long range. The Tau Hammerhead, by virtue of range, firepower, or survivability, also compares favorably to every other main battle tank in the game. Eldar lack range, Imperials generally lack survivability and firepower- with occasional exceptions, like Vindicators, that lack range. The Tau are a special snowflake, because they are the ONLY faction in 40k still developing technologically.

The Conversion Beamer would like to have a word.

Will it start with what tank chassis it's mounted on? Perhaps the name of the Forge World capable of producing it? I'm pretty sure you're not mentioning it as a standard-issue rifle or as something the Imperium has developed recently. Heck- only a Master of the Forge can use it without it exploding.

The Conversion Beamer is man-portable. Especially if that man happens to be a Skitarii or Space Marine.

http://wh40k.lexicanum.com/wiki/Conversion_beamer#.VCMRGJRdVKY

And in the Dark Age of Technology, they *were* very common. What the Tau now possess is *nothing* to the technological marvels Mankind possessed in its Golden Age, wherein the Baneblade was considered a light battle tank and the Rhino was just a tractor.

 Frozen Ocean wrote:
I believe that the Warp Storm that shielded the Tau from the Imperium (and sped up their development, perhaps so they would be ready for whatever their purpose is in time) was caused by the Eldar. Not Harlequins, but a Craftworld or a number of Craftworlds working to fulfill some hope for the future that the Tau play an instrumental part of.

However, that doesn't mean that the Tau will be the saviors of the Eldar. Butterfly effect, and all that. The existence of the Tau may have unnoticed (by everyone else) and unintentional benefits for the Eldar. They might be wiped out by something that would have otherwise harmed the Eldar. In short, their intended purpose could be very, very subtle, and there's no way of knowing what it means for the future of the Tau.

Also, I think it's less that the Tau have a small Warp signature and more that they actually are essentially very mild Blanks. This would explain why they can't be Warped while inanimate objects (which have no Warp signature whatsoever) can with ease.

That makes no sense, blanks can't be seen by Warp entities, which would mean that fight Farsight had should never have happened. Also if they were blanks all the Imperium psykers that came across them would freak out, and not even GW would do a retcon of that scale.

Quickjager wrote:

 Frozen Ocean wrote:
I believe that the Warp Storm that shielded the Tau from the Imperium (and sped up their development, perhaps so they would be ready for whatever their purpose is in time) was caused by the Eldar. Not Harlequins, but a Craftworld or a number of Craftworlds working to fulfill some hope for the future that the Tau play an instrumental part of.

However, that doesn't mean that the Tau will be the saviors of the Eldar. Butterfly effect, and all that. The existence of the Tau may have unnoticed (by everyone else) and unintentional benefits for the Eldar. They might be wiped out by something that would have otherwise harmed the Eldar. In short, their intended purpose could be very, very subtle, and there's no way of knowing what it means for the future of the Tau.

Also, I think it's less that the Tau have a small Warp signature and more that they actually are essentially very mild Blanks. This would explain why they can't be Warped while inanimate objects (which have no Warp signature whatsoever) can with ease.

That makes no sense, blanks can't be seen by Warp entities, which would mean that fight Farsight had should never have happened. Also if they were blanks all the Imperium psykers that came across them would freak out, and not even GW would do a retcon of that scale.

Think blanks without the anti-psyker bit. They have no psykers and most psychic things that are not something like a physical attack will not harm them.

 Co'tor Shas wrote:

Quickjager wrote:

 Frozen Ocean wrote:
I believe that the Warp Storm that shielded the Tau from the Imperium (and sped up their development, perhaps so they would be ready for whatever their purpose is in time) was caused by the Eldar. Not Harlequins, but a Craftworld or a number of Craftworlds working to fulfill some hope for the future that the Tau play an instrumental part of.

However, that doesn't mean that the Tau will be the saviors of the Eldar. Butterfly effect, and all that. The existence of the Tau may have unnoticed (by everyone else) and unintentional benefits for the Eldar. They might be wiped out by something that would have otherwise harmed the Eldar. In short, their intended purpose could be very, very subtle, and there's no way of knowing what it means for the future of the Tau.

Also, I think it's less that the Tau have a small Warp signature and more that they actually are essentially very mild Blanks. This would explain why they can't be Warped while inanimate objects (which have no Warp signature whatsoever) can with ease.

That makes no sense, blanks can't be seen by Warp entities, which would mean that fight Farsight had should never have happened. Also if they were blanks all the Imperium psykers that came across them would freak out, and not even GW would do a retcon of that scale.

Think blanks without the anti-psyker bit. They have no psykers and most psychic things that are not something like a physical attack will not harm them.

So? Kroot don't have psykers, they aren't blanks. And to say that most psychic things that are not attacks don't affect has no backing because they have never been put in a position like that.

Quickjager wrote:

 Co'tor Shas wrote:

Quickjager wrote:

 Frozen Ocean wrote:
I believe that the Warp Storm that shielded the Tau from the Imperium (and sped up their development, perhaps so they would be ready for whatever their purpose is in time) was caused by the Eldar. Not Harlequins, but a Craftworld or a number of Craftworlds working to fulfill some hope for the future that the Tau play an instrumental part of.

However, that doesn't mean that the Tau will be the saviors of the Eldar. Butterfly effect, and all that. The existence of the Tau may have unnoticed (by everyone else) and unintentional benefits for the Eldar. They might be wiped out by something that would have otherwise harmed the Eldar. In short, their intended purpose could be very, very subtle, and there's no way of knowing what it means for the future of the Tau.

Also, I think it's less that the Tau have a small Warp signature and more that they actually are essentially very mild Blanks. This would explain why they can't be Warped while inanimate objects (which have no Warp signature whatsoever) can with ease.

That makes no sense, blanks can't be seen by Warp entities, which would mean that fight Farsight had should never have happened. Also if they were blanks all the Imperium psykers that came across them would freak out, and not even GW would do a retcon of that scale.

Think blanks without the anti-psyker bit. They have no psykers and most psychic things that are not something like a physical attack will not harm them.

So? Kroot don't have psykers, they aren't blanks. And to say that most psychic things that are not attacks don't affect has no backing because they have never been put in a position like that.

I said they were like blanks, not that they were blanks. The kroot actuly have some psychic ability, shapers have a very small amount. And with most psycic things I am talking about telepathy and possession.

And like I said, they have never come up against anything that uses those tactics.

The imperium, deamons, chaos, ect.

We lack sufficient fluff representative of the Tau to say for certainty whether they're immune to it. However, since they are explicitly *not* Untouchables, then the fact that they have no active psykers in their race (or do they? The Etherals might be, the pheromone thing is demonstrably false) doesn't mean anything. There's plenty of non-psychic races that are subject to psychic effects (such as the Necrons, both pre-and-post Biotransference)... and *there's* a race that didn't have any psykers at all and were not Untouchables.

However, the fluff we do have suggests that they are nearly-invisible in the Warp ("nearly invisible" is not "totally invisible"), and so are kind of a pain in the ass for a Daemon to possess... but if a Daemon were really interested in doing it, there's so far been nothing stating that it would be impossible.

Imperium doesn't use possession, Tau haven't fought Chaos marines or sorcerers, the Etherals make sure they always avoid deamons.

Now why would the Etherals avoid deamons actively? Why would they hide this knowledge? Is it because they are susceptible to Chaos?

Besides if they aren't BLANKS then telepathy should work in some form.

Psienesis wrote:

Also, I think it's less that the Tau have a small Warp signature and more that they actually are essentially very mild Blanks. This would explain why they can't be Warped while inanimate objects (which have no Warp signature whatsoever) can with ease.

But they can be. They can definitely receive the benefits of Warp-based "technologies" (is why Farsight is still alive), which implies that they are likewise subject to the corrupting effects of Chaos. If, say, a Tzeentchian Sorcerer were to blast a Fire Warrior with a Bolt of Change, you'd expect that Fire Warrior to sprout tentacles and beaks and otherwise collapse in a screaming, mewling pile of rapidly-mutating flesh.

Isn't the Dawn Blade heavily implied to be a Necron artefact? Still, it's possible that it's a strange form of healing device that is just powered by Warp energies, somehow. We've seen weirder stuff being done with Warp technology. Regardless, you might be on to something, but the effects of a given spell don't necessarily have to mean the target is susceptible to Chaos. A good example is a Warp Lance from a Tyranid Zoanthrope - it's an explosion that just so happens to be powered by psychic energy (which is why I hate how Deny the Witch used to work), and only the ability to straight up absorb or negate Warp energy (for example, a Culexus) should do much good against that. There does seem to be a degree of disconnect between direct "spells" and the workings of Chaos. I imagine a Bolt of Change could be just as effective on a Necron Warrior for this reason.

Quickjager wrote:

 Frozen Ocean wrote:
I believe that the Warp Storm that shielded the Tau from the Imperium (and sped up their development, perhaps so they would be ready for whatever their purpose is in time) was caused by the Eldar. Not Harlequins, but a Craftworld or a number of Craftworlds working to fulfill some hope for the future that the Tau play an instrumental part of.

However, that doesn't mean that the Tau will be the saviors of the Eldar. Butterfly effect, and all that. The existence of the Tau may have unnoticed (by everyone else) and unintentional benefits for the Eldar. They might be wiped out by something that would have otherwise harmed the Eldar. In short, their intended purpose could be very, very subtle, and there's no way of knowing what it means for the future of the Tau.

Also, I think it's less that the Tau have a small Warp signature and more that they actually are essentially very mild Blanks. This would explain why they can't be Warped while inanimate objects (which have no Warp signature whatsoever) can with ease.

That makes no sense, blanks can't be seen by Warp entities, which would mean that fight Farsight had should never have happened. Also if they were blanks all the Imperium psykers that came across them would freak out, and not even GW would do a retcon of that scale.

That's why I said "essentially very mild Blanks". They aren't Blanks, but they do have something unique about them that is definitely anti-Warp, not just lacking in Warp signature.

Quickjager wrote:
Imperium doesn't use possession, Tau haven't fought Chaos marines or sorcerers, the Etherals make sure they always avoid deamons.
Interesting, so you know every single battle that the tau have ever fought do you?
Now why would the Etherals avoid deamons actively? Why would they hide this knowledge? Is it because they are susceptible to Chaos?
No clue, best to chop it up to the old distopian society/don't want your soldier to be scared shitless.
Besides if they aren't BLANKS then telepathy should work in some form.
They just can't hear it.

 Frozen Ocean wrote:
I believe that the Warp Storm that shielded the Tau from the Imperium (and sped up their development, perhaps so they would be ready for whatever their purpose is in time) was caused by the Eldar. Not Harlequins, but a Craftworld or a number of Craftworlds working to fulfill some hope for the future that the Tau play an instrumental part of.

However, that doesn't mean that the Tau will be the saviors of the Eldar. Butterfly effect, and all that. The existence of the Tau may have unnoticed (by everyone else) and unintentional benefits for the Eldar. They might be wiped out by something that would have otherwise harmed the Eldar. In short, their intended purpose could be very, very subtle, and there's no way of knowing what it means for the future of the Tau.

Also, I think it's less that the Tau have a small Warp signature and more that they actually are essentially very mild Blanks. This would explain why they can't be Warped while inanimate objects (which have no Warp signature whatsoever) can with ease.

What makes you think that it is the Craftworld Eldar specifically involved in it? If the Eldar have the tech to create Warp Storms, as in sector wide ones, we have not seen it yet. And if a specific Craftworld did this, which do you suggest. The only known craftworld even remotely near the Tau Empire in the galaxy are Iyanden, with every other one being half a galaxy away. Add that to the fact even Eldrad doesn't know why he feels protectiveness towards the Tau, that means he wasn't involved, which rules out Ulthwe. So what's your line of thinking?

Theoretical battles that have no depiction in the fluff, or even reference or implication, cannot really be used to prove a point.

Otherwise, I can simply say "the Tau exist to be exterminated utterly, because the Imperium is GW's favorite faction, and that's what the Imperium does to aliens" and that will be the end of that.

Isn't the Dawn Blade heavily implied to be a Necron artefact? Still, it's possible that it's a strange form of healing device that is just powered by Warp energies, somehow. We've seen weirder stuff being done with Warp technology. Regardless, you might be on to something, but the effects of a given spell don't necessarily have to mean the target is susceptible to Chaos. A good example is a Warp Lance from a Tyranid Zoanthrope - it's an explosion that just so happens to be powered by psychic energy (which is why I hate how Deny the Witch used to work), and only the ability to straight up absorb or negate Warp energy (for example, a Culexus) should do much good against that. There does seem to be a degree of disconnect between direct "spells" and the workings of Chaos. I imagine a Bolt of Change could be just as effective on a Necron Warrior for this reason.

Implied, but there's plenty of other sources it could be from (and, also, if it's pre-Biotransference, then it's just as susceptible to corruption as any other mundane object)... but we have to ask ourselves, why would an immortal robot need a weapon that drains life to make it live longer? That makes no logical sense from a CrypTek's perspective.

Warp energy is Psychic Energy is Daemonic Energy. It's all from the same source. The table-top rules, unfortunately, don't often take this into account or they use the same name for two or more different attacks when they are not identical. This is how it is with the Tyranids, in that their "psychic" attacks and such are not Warp-based, but instead are based on the Hive Mind... so the Untouchable trait possessed by some targets simply provides no protection.

 Psienesis wrote:
The Conversion Beamer is man-portable. Especially if that man happens to be a Skitarii or Space Marine.

http://wh40k.lexicanum.com/wiki/Conversion_beamer#.VCMRGJRdVKY

And in the Dark Age of Technology, they *were* very common. What the Tau now possess is *nothing* to the technological marvels Mankind possessed in its Golden Age, wherein the Baneblade was considered a light battle tank and the Rhino was just a tractor.

I'm sure the long-lost glories of the DAoT were very consoling when the Tau fought off the Taros invasion.

Even if it was common, they're so rare that they are held only by the most elite of technology-worshippers and so hard to use... they're pretty much only used by the most elite of technology-worshippers.

Even then, you only get to hit like a rail gun at the longest of ranges. A railgun still hits like a railgun at less than 42 inches.

To finish- the conversion beamer is impossible to mass-produce, incredibly rare, and less adaptable than a railgun.... and that's supposed to be heartening to the Imperium.

 Co'tor Shas wrote:

Quickjager wrote:
Imperium doesn't use possession, Tau haven't fought Chaos marines or sorcerers, the Etherals make sure they always avoid deamons.
Interesting, so you know every single battle that the tau have ever fought do you?
Now why would the Etherals avoid deamons actively? Why would they hide this knowledge? Is it because they are susceptible to Chaos?
No clue, best to chop it up to the old distopian society/don't want your soldier to be scared shitless.
Besides if they aren't BLANKS then telepathy should work in some form.
They just can't hear it.

Go on, show me somewhere in fluff the Tau fought against daemons wanting to possess them. Come on, not even in Fire Warrior did they try to possess them.

 Psienesis wrote:
Theoretical battles that have no depiction in the fluff, or even reference or implication, cannot really be used to prove a point.

I'm assuming this is directed at me.

Fire warrior. Plenty of chaos fighting right there.

Also, although this is old fluff, The air caste is currently guarding/watching a large patch of space where the warp is "closer" and they stop demonic incursions by blowing them up.

 Psienesis wrote:
)... but we have to ask ourselves, why would an immortal robot need a weapon that drains life to make it live longer? That makes no logical sense from a CrypTek's perspective.

They weren't always robots.

EmpNortonII wrote:

 Furyou Miko wrote:


The Destroyers are the result of encroaching madness due to isolation and faulty stasis cells. You're thinking of Flayed Ones when you talk about C'tan influence.

Third paragraph in the Destroyer entry mentions that the C'tan may be responsible for them about halfway through.

May be responsible, older fluff offers other potential reasons. I'll take your lack of comments on my other points as admittance that I'm right.

Psienesis wrote:The Conversion Beamer is man-portable. Especially if that man happens to be a Skitarii or Space Marine.

http://wh40k.lexicanum.com/wiki/Conversion_beamer#.VCMRGJRdVKY

And in the Dark Age of Technology, they *were* very common. What the Tau now possess is *nothing* to the technological marvels Mankind possessed in its Golden Age, wherein the Baneblade was considered a light battle tank and the Rhino was just a tractor.

The Rhino was derived from an exploration / colony vehicle, you're thinking of the Leman Russ.

Presumably the DAoT's "heavy tanks" were something like a BOLO.

Even better! The LR was a tractor, and the Rhino was a Jeep!

ALEXisAWESOME wrote:
What makes you think that it is the Craftworld Eldar specifically involved in it? If the Eldar have the tech to create Warp Storms, as in sector wide ones, we have not seen it yet. And if a specific Craftworld did this, which do you suggest. The only known craftworld even remotely near the Tau Empire in the galaxy are Iyanden, with every other one being half a galaxy away. Add that to the fact even Eldrad doesn't know why he feels protectiveness towards the Tau, that means he wasn't involved, which rules out Ulthwe. So what's your line of thinking?

I don't know! There are a lot of Craftworlds we don't know about, though. Maybe they had some cool artefact, or maybe they just had a lot of psykers working together to direct an existing Warp Storm to the right place and time. Maybe this action proceeded the actual manifestation of the storm by many thousands of years or more.

Psienesis wrote:
Implied, but there's plenty of other sources it could be from (and, also, if it's pre-Biotransference, then it's just as susceptible to corruption as any other mundane object)... but we have to ask ourselves, why would an immortal robot need a weapon that drains life to make it live longer? That makes no logical sense from a CrypTek's perspective.

I'm not sure. "Immortality" is a bit too much to be an unintended side-effect of a weapon that was meant for fighting the Old Ones, I suppose, but it doesn't have to be Necrons.

Psienesis wrote:Warp energy is Psychic Energy is Daemonic Energy. It's all from the same source. The table-top rules, unfortunately, don't often take this into account or they use the same name for two or more different attacks when they are not identical. This is how it is with the Tyranids, in that their "psychic" attacks and such are not Warp-based, but instead are based on the Hive Mind... so the Untouchable trait possessed by some targets simply provides no protection.

Do Blanks not receive protection from Tyranids in fluff? I'm not sure, I've never seen it come up. I believe that the Warp is just a local (to the Milky Way) field of psychic energy, and that the Tyranid Hive Mind is essentially their own "Warp", which is incompatible and very different to the thing we call the Warp, but the "energies" are still roughly the same and follow the same rules, more or less (anything that doesn't involve Synapse or Chaos Gods). Still, there is definitely some degree of difference between psychic powers being cast on things and just the Warp corrupting and Daemons doing their thing. Necrons are much the same as the Tau in the sense that they have some degree of Warp protection. They can't be possessed or corrupted but they can be influenced by psychic powers, as far as I know.

 EmpNortonII wrote:

 Psienesis wrote:
)... but we have to ask ourselves, why would an immortal robot need a weapon that drains life to make it live longer? That makes no logical sense from a CrypTek's perspective.

They weren't always robots.

Indeed. And in the Time of Flesh, even though they had no Psykers themselves, they were most-definitely affected by Psychic attacks, as when the Necrons launched their war against the Old Ones, they got wtfspanked by those psychic space-lizards.

Do Blanks not receive protection from Tyranids in fluff? I'm not sure, I've never seen it come up. I believe that the Warp is just a local (to the Milky Way) field of psychic energy, and that the Tyranid Hive Mind is essentially their own "Warp", which is incompatible and very different to the thing we call the Warp, but the "energies" are still roughly the same and follow the same rules, more or less (anything that doesn't involve Synapse or Chaos Gods). Still, there is definitely some degree of difference between psychic powers being cast on things and just the Warp corrupting and Daemons doing their thing. Necrons are much the same as the Tau in the sense that they have some degree of Warp protection. They can't be possessed or corrupted but they can be influenced by psychic powers, as far as I know.

Not that I'm aware of. Since they're Blanks, they're not subject to the Shadow In The Warp (and wouldn't be, anyway, if they were mundane people), but I've never heard of a Blank being able to ignore, like, the psychically-generated shrieks or similar Hive Mind-sourced "psychic" attacks of the Tyranids. I simply am not aware of any books covering such specific scenarios. I do remember, though, that Codex: Tyranids.... I wanna say 3E?... made it explicit that Tyranid Psychic Powers were not Psychic Powers as possessed by the other races, and explicitly did not use Warp Energy.

The Necrons, even in their current bodies, can most *definitely* be affected by Chaos. That is why they go to such pains to set up anti-Warp and Psychic Null Fields around their Tombs. It is even stated in Codex: Necrons that daemons love the Necrons for all their hyper-dimensional shenanigans, as these lead the Daemons to "new flavors of reality to corrupt".

Blanks can nullify the Synaptic Web of the Tyranid Hive Mind or Genestealer Brood Mind, causing confusion among Tyranids as if their synaptic link had been severed. Blanks are also painful to touch for Daemons are extremely distressing for Psykers, and while if they are targetted or get in the way or a Witchfire it will dissipate, they cannot stop the Psyker effecting themselves or things around them. In other words they can survive a bolt of change, but not having a levitating tank dropped on their heads. This is what you learn from Jurgan in the Commissar Cain books.

Tau are not Blanks, they are Blunts. They are completely oblivious to the world of the warp and the warp has little effect on them indirectly, but unlike a blank, someone can shoot warp lightning at you and you will still die. A Daemon can still invade your mind and possess your body, but they cannot ''convince'' you to do something with mind speech alone.

I don't know! There are a lot of Craftworlds we don't know about, though. Maybe they had some cool artefact, or maybe they just had a lot of psykers working together to direct an existing Warp Storm to the right place and time. Maybe this action proceeded the actual manifestation of the storm by many thousands of years or more.

Doesn't it just make more sense for the Harlequins to of done it though? If the Eldar had the Tech to make a Warp Storm, then you can bet your barnacles that it will be found in the Black Library. What do Craftworld Eldar know of Blanks? Very little, while one of the Harlequin characters, the Solitaire, is the Blank Supreme. Plus, the Harlequins are the only Eldar party who's God actively plays a part in their plans. If anyone has a Plan, it's Cegorarch, and it will invariably be anti-chaos. Seems to fit the bill to mean, Means and Motive.

If so, they chose a really bad place to stick them. There's a dozen Space Marine Chapters within spitting distance of their miniscule empire, and the Imperium is not exactly known for its friendly foreign relations.

 EmpNortonII wrote:

 Psienesis wrote:
The Conversion Beamer is man-portable. Especially if that man happens to be a Skitarii or Space Marine.

http://wh40k.lexicanum.com/wiki/Conversion_beamer#.VCMRGJRdVKY

And in the Dark Age of Technology, they *were* very common. What the Tau now possess is *nothing* to the technological marvels Mankind possessed in its Golden Age, wherein the Baneblade was considered a light battle tank and the Rhino was just a tractor.

I'm sure the long-lost glories of the DAoT were very consoling when the Tau fought off the Taros invasion.

Even if it was common, they're so rare that they are held only by the most elite of technology-worshippers and so hard to use... they're pretty much only used by the most elite of technology-worshippers.

Even then, you only get to hit like a rail gun at the longest of ranges. A railgun still hits like a railgun at less than 42 inches.

To finish- the conversion beamer is impossible to mass-produce, incredibly rare, and less adaptable than a railgun.... and that's supposed to be heartening to the Imperium.

There is a chance there are more conversion beamers than railguns in the galaxy. I think you are struggling the the difference in scale between the Imperium and the Tau. But you seem to be struggling with much of those sorts of things. You certainly wear your bias on your sleeve!

 Psienesis wrote:
If so, they chose a really bad place to stick them. There's a dozen Space Marine Chapters within spitting distance of their miniscule empire, and the Imperium is not exactly known for its friendly foreign relations.

Maybe the Harlequins preferred the Tau's location because it protected them from direct material physical Chaos attack until they've had time to grow. For example, if Tzeentch got wind of the Harlequin's plans and the Tau were close to the Eye of Terror, Chaos might have crushed them early on. At their current location, it might be difficult for even Tzeentch to pull something off that could get enough Chaos forces over there to anhilate them (at least, pull something off in a short time-span. In a longer time-span he could probably do it but by then the Tau would have grown stronger).

Hypothetically and theretically, of course.

Seems a super-risky gamble. "Might get Chaos attacked... or will almost certainly get exterminated by the Imperium of Man. Hmm..."

The Tau could just as easily be a denial play against possible plots by other diviners?

For the Warp Storm, if it were Eldar, we only know that the relevant parties belived there was a warp storm. It's entirely possible it was faked - something Eldar do well. Or Tzeech, but he could do an actual storm.

For Tzeech, remember that, to him, the game must be played. It could be a Tzeechian plot against Tzeech himself. Or a Tzeechian counter to a Tzeechian plot. Or a counter to a counter to a counter. The Game must be played.

As for the Sword possibly being Necron (Chaos and Eldar are both reasonable theories as well), a post-biotransferrence cryptek could have created it in an experiement, and the life-extension is just a side-effect or failure. Their tech truly is amazing.

When it comes to their tech versus other races, comparing the Pulse Rifle to the Lasgun seems relevant, because they're both line infantry with relatable - but not identical - doctrines.
Necron line infantry has a different doctrine. Walk forward. Shoot any threat. Walk forward. Shoot. Necrons aren't threatened by most small arms, and even if they do get a lucky shot, that model will just rematerialize. For that doctrine, the Necron weapon is far superior, as there is nothing it can't destroy just by shooting. Pulse Rifles can't handle medium tanks or better.
Eldar line infantry are Tau, Orks, or whoever else is around. Shuricats are more sidearms.
So the two races with tech better than Tau don't really have weaker line infantry weapons. Just different.

While the Warp Storm-fakeout is possible, there's too many holes in the theory for it to be plausible. Mainly, apart from the massive technological evolution of post-Storm Tau, they had (far more importantly) undergone thousands of years of cultural and societal evolution.