Well the Imperium has many options available to it when performing Exterminatus. The word isn't a reference to a specific method of destruction brought down upon the world, but am archetypica action.

From the myriad sources found in the fluff, it appears that a fleet isn't really necessary, it just makes things a lot more expedient and certain to kill everything. We only have to look at the case of 57-Izar, where they hit the major population centres of the Saruthi with orbital strikes, then virus bombed the planet, and then nuked the planet.

While Istvaan was just some virus bombs, by multiple ships. But considering it's an airborne virus that kills anything, I don't even think a flotilla is necessary, if you launch a high enough yield in to the upper atmosphere where it can rain down on a large portion of the planet, and be carried around by air currents. And that alone would be enough, since only those things living in the deepest caves or parts of the ocean (or sealed bunkers) would have a chance of escaping contact with the Life Eater virus.

Similarly, it's suggested that a potential follow-up to /Extraction/ is to have *the PCs* enact Exterminatus on the planet...

I'd say the biggest reason is in fact the desire for habitable worlds. Which it is.

But there's a few more reasons. One is that the Tau protect a flank against the Tyranids. Which is why the initial crusade against them was called off to begin with.

Another is that they really are -not- a threat. Exterminatus is the sort of thing that is used only to save massive regions. You don't destroy a world just because. You destroy a world when the contamination is so total, so complete that it can never, ever be saved. And even then only if it has a chance of spreading out and destabilizing the entire sector or segmentum. The Tau aren't even close to that level.

And when it comes right down to it? The Tau have -never- been a threat to the Imperium. An annoyance, perhaps. But not a threat. they were made from the get go as an example of a minor alien power that the Imperium deals with. The truth of the matter is they're so minor they haven't even been worth the effort to wipe out. And if the Imperium wanted to, they could grind them into dust rather quickly with a full on crusade. Hell, even the initial crusade was only because of an underestimation of their size making it stall out. They were planning to fall back and regroup with a full on crusade of the right size to wipe out the empire and take their worlds when the Tyranids showed up, and the military forces of the region were needed for a real threat.

So really, the only thing saving the Tau is their complete lack of puissance in the overall scheme of things.

Dulahan said:

But, at the same time, they represent just what a minor Xenos empire can achieve against an Imperium which is beset from all sides - the Imperium literally cannot spare the time, effort or resources to annihilate the Tau, and thus the Tau don't merely survive, but prosper, chipping away at the edge of the Imperium with a combination of warfare, trade and diplomacy.

They're not a galactic threat, no... but they're one amongst many of the enemies of Man, and dangerous in their own right, because they're underestimated (this goes both ways; the Tau don't really understand how massive the Imperium is), because they're not purely a military threat, and because they've been left largely unopposed for centuries. There's nothing to say that, hypothetically, the Tau won't be a real threat centuries down the line... but if the Imperium doesn't act against them, then the Tau do have a very real opportunity to try and become a much more significant presence.

Dulahan said:

^^This

Heck, I'd go so far as to say that in the case of Ordo Xenos, it should only be used for completely incompatible and overwhelming cases like Tyranids (when they're at the stage of wiping the whole planet out anyways), or complete Enslaver domination. Or maybe a massive Necron Horde.

Hell, even an Orkworld is probably worth not wiping out via Exterminatus. Unless it would stave off a truly colossal Waaaaaagh! (likely one requiring quite a few more "A"s than I wrote. ).

Admittedly, one too Radical might. But there are strictures in place to deal with those sorts and punish them for it. Note how even Kryptman got some major gruff for a few strategic ones that were directly responsible for helping stop a Hive fleet! A HIVE FLEET! That's about as bad as it gets. Yes, many thought Exterminatus was too far in that case alone. So yeah, the Tau don't even come close to warranting Exterminatus. The Imperium thinks in the relatively long term (Nothing like the Eldar, but still capable of plans hundreds of years in the execution). And ultimately, they can deal with the Tau. Eventually.

N0-1_H3r3 said:

Which is trading in 'maybes', and as such it's a great reason *not* to trash a habitable planet for all time.

Ultimately, habitable planets are pretty much the only finite resource that the Imperium has in the long-term. It doesn't matter if it costs hundreds of billions of lives to take a planet, because they can be replaced. Planets can't. Plus: It's make for a poor game if every conflict was solved not by a skirmish wargame / game of Epic, but by just blowing up the planet.

It's why the Tyranids are such a threat: They essentially destroy planets.

To be fair, I think that was N01-H3R3's point - there's sort of a paradox with the Tau: leave them be, and a thousand years from now they might destroy the Imperium, commit resources to destroying them, and the Imperium might fall tomorrow.

A planetary extinction event is hard to do, even in 40K.

The Russian 50 megaton nuke was never designed as a weapon because it was too **** big to be deliverable to an enemy half way across the planet. Even gigaton level energies won't cause an extinction events. VolcanoThe 2004 Tsunami was around 9,560 gigatons and while it sucked to be in a coastal region hit by it, it wasn't civilization ending by a long shot. Add in things like void shields and planetary defence lasers and bombardment with heavy missiles or asteroids becomes problematic.

Virus bombs, cyclonic torpedoes, and Exterminator stealth ships don't grow on trees. They're rare and expensive technology and their success isn't guarranteed. From the Imperial point of view the Tau are a minor alien race with potent technology. Burning a world is a big step. Is it worth expending such rare weapons and endangering such a precious ship to attempt to burn a viable planet? From the Imperial point of view the Tau are just another minor alien race they're going to wipe out. It's a big risk to take and a lot of resources to invest in burning a planet that is a prize that can be taken with enough blood and effort from much more replaceable ships and men. Archeotech and near archeotech resources do not grow on trees and neither do habitable planets.

Siranui said:

Siranui said:

And not just destroying planets but converting it's biomass into more Nid constructs. As rare as it is Exterminatus might be prefferable on, for example an Agriworld, like in the Extraction scenario. But here's some bullet points of what I think:

1. Regardless of their overall threat level a main Xeno stronghold from any of the major Xeno players, such as Tsua'malor, is likely to have defences that anticipate attacks by cloaked ships wheather to destroy the planet or beam down a kill team of asassins. Both the Eldar, Dark Eldar, Necrons and Tau have significant stealth tech themselves and much in the way of psychic or technological advances that can no doubt be employed. The chaos forces probably have comanders that fought empires that used such tech in the Crusades, Nids don't hold planets unless they are eating them, probably get away with it against orks unless a Mekboy has a stroke of genius.
2. I don't think I like the idea of the Killships themselves, I don't know if they were mentioned in a book before but, they've got a huge vessals entirely operated by machine spirits. No I'm sure I'm going to be corrected but wouldn't the Ad Mech have something (and wouldn't you need the Ad Mech to make them) to say about entire ships being run by AI, I'm sure I read somewhere that it's a matter of debate weather a Landraider Machine Spirit is against the omnissiah let alone a major warship that you have loaded with planet destroying weaponry.
3. As far as I can remember, and you'll correct me again, isn't the Inquisition the only ones allowed to call for an Exterminatus and not a SM chapter. And the DW rulebook goes quite some way to make clear that DW are not part of the Inquisition but mearly allied to it.

Cynical Cat said:

Unless you happen to be Deathwatch, in which case you have hundreds of the things laying around.

Siranui said:

Hundreds of the things but they are hard to replace and spread out over an entire galaxy of 200 billion stars and many, many enemies. The Tau are fairly easy to exterminate compared to the unending hordes of Tyranid warriors who will strip a planet figuratively to the bone and use that to create and fuel another titanic horde. With the 'Nids the planet is lost once it's overrun. There's no future productivity to consider and a giant horde that can be destroyed before it is ever born. A much better target for scarce hyper tech weapons that are only produced on a handful of worlds.

No: Hundreds of them very specifically sat there in Erioch, armed and read to rock!

the Tau are simply no real threat to the Imperium of Man. they expand slow for the lack of warp drive, it is possible to negotiate with them, and the will run home to Mommy if you punch them hard enough in the face.

Orks & Tyranids dont! You have to kill them ALL to stop an invasion and thanks to their reproduction mechanics a planet once tainted can never again be considerd 100% clean of them.

Siranui said:

Source for that?

The main books has quite a different take on the ships and weapons available at Fortress Erioch.

Page 330 of Deathwatch:

"Watch Fortress Erioch also has extensive void docks in which a dozen capital ships or battle barges could be docked and resupplied at the same time."

That's not hundreds by a long shot.

Also on page 330, discussing the greatest weapons available, including the life eater virus. "Most secret of all are the terrible devices kept in the outer catacombs of the Omega Vault, the great sealed chamber at the heart of Watch Fortress Erioch. . . . These weapons are only yielded one at a time and by the will of the systems that lie at the centre of the Vault's many chambers, watching and waiting for the future."

It's clear they have some Exterminatus weapons, but they're under such security that they'll only be used when the necessity is dire. That's not Exterminatus spam.

Rites of Battle, where the Kill-Ships themselves are detailed.

Blood Pact said:

They're detailed in both the main book and Rites of Battle. Page 247 of Rites of Battles says there are dozens of Kill Ships, not hundreds, and the text implies that they're being held in reserve for something truly terrible. Of course half the pages of any Deathwatch book imply the visible threats to the Jericho Expanse pale in comparison to the hidden horrors that may soon awake, so that's perfectly consistent with the rest of the material and not wanting to risk a Kill Ship and expend its precious ordinance on such a mundane target as Tau.

Plus of course, as a Kill Ship doesn't have a Navigator it can't actually be sent anywhere that isn't on the established warp routes it has in it's records based on short jumps.

Plus I don't like it's chances of coming back in one peice if it's grand strategy is catapult it's way out based on the planets own gravity, as if no one else thought about that at all. Which points them being a bit of desperation weapon.

Narkasis Broon said: