Situation in Castobel: Splinter part of the Tyranid hivefleet has besieged the planet. Two out of six hive cities have fallen. PDF is ripped to shreds, barely able to keep its current positions. No communication in or out of the system is possible without very special arrangements. However, the Tyranids are not all too well themselves. The surface of the planet is lifeless and unless they can get inside the hive cities for nomnoms they are sustaining their operations using the biomass of the hive fleet alone.

Now here is an interesting question:

Lets assume that, for some strange reason someone (lets say Deathwatch) would actually want to stop the Tyranids and save the planet how would it be possible? It seems the Imperial policy when hive fleet has landed somewhere is usually jsut evacuate the most important personnel and then just call Extreminatus on the whole planet. But what if they really wanted to make a difference and not just callously sacrifice the whole population of the planet... What (if anything) could be done?

All ideas are helpfull and maybe you'll see some of them in my Campaign log one day...

Clean sweep the Orbit with every Battelship/Cruiser/Escort you have. When you are succsesfull and the reinforcment line for the Nids is cut off, take every Man capable of holding a gun and beginn the long (perhaps eternal) struggle to clean up the planet of everything that has more than 2 arms or legs.

the only way if you want to preseve the planet...

I would suggest denial of biomass at every possible engagement. Burn or otherwise destroy all casualites on both sides, while still prioritising the destruction of the larger targets, both for leadership and for the the biomass required to replace them. Try to use automated defences, booby traps or anything else that means an inverse amount of biomass from defender to attacker...

Destroy the Tyranid C3 by taking out the core aspects of the hive mind, sweep the local space clear by fleet action to prevent reinforcement dirt-side, seek and destroy other neural creatures, then start work on killing every nid left, as they should pretty much all be effectively driven insane by now and won't be replacing losses or acting in any sensible manner.

Or just prevent them from replacing biomass (via scorched earth and driving off the enemy fleet and blockading the planet via fleet action) before finding and killing everything left and simply attrite them.

The first option is much more Deathwatch, as it panders to using a small, elite spearhead; whereas option 2 just requires a big fleet, a bunch of IG, and lots of napalm. Either way, you need to prevent the tyranid fleet reinforcing the planet, which will almost certainly require a fleet to do.

1.Clean the orbit first and then use Life Devourer Virus...yeah, it will do some collateral damage. But this is the Imperium

2.Use the "Oblivion's Edge" method: Send a Kill-Team inside the biggest hive ship you can see and destroy its synapse node. Then, destroy the headless swarm.

3.Use the "Dawn of War 2 /Uriel Ventris on Tarsis Ultra" method: Obtain a pure sample of DNA of this splinter and then develop a venom against it. Then, release it in the digestive pools/ air propagation.

4.Use the Tau method against Gorgona fleet: destroy their reproductor creatures and monsters and let the tide crash on your battle line for last time.

5.Commisar's voice: HOLD THE LINE! FOR THE GOD-EMPEROR! ONE DAY, THE HELL WILL RUN OUT OF MONSTERS!

6.Use Kryptman's method: Kidnap a Genestealer brood and liberate them in a Tau planet. Let the xenos kill between them.

7. Ask Ordo Xenos, they will know an artefact or tactic or virus or whatever to kill them all in one blow.

8.Use Behemoth's hive fleet method: Open a warp rift in the middle of the fleet using a suicide Emperor Class Batlebarge. Expensive, but effective.

9"..I love the smell of napalm in the morning " method

10. Call several Kill-Teams in the planet, and make them organise the defence: instruct the Guardsmen (use this side of the knife) rise their morale, teach them about tactics. Then, place your Deathwatch Marines in the worst of the attack. You can save the world with 30 marines instead of using a Company or two. The ideal proportion would be a team per hive city. But life in the Imperium isn't always ideal.

11. And if all fails...you can always pray to the Chaos Gods.

Burn their fleet, kill the spawning pools. Whether it's with ground based target locks, or a saturation bombardment.

Break the swarm hard enough that it cannot grow to be world threatening unless unchecked.

Raise a lot of PDF.

Leave.

You now have a planet which will produce many fine regiments of Tyranid fighters.

Mentioned before, but the most effective way is probably to destroy the hive ships, starting with the biggest. Once the lesser creatures lose connection to the Hive Mind things become a lot easier.

Developing a targeted virus also seems to work, though I'm not sure that would be feasible in every situation.

Usually the most simple, yet risky and sucidal method is the one previously mentioned used in Dawn of War 2: obtain the purest DNA samplest you can, and put the apothecaries to produce a very nasty toxine, then inject it into the feeding tendrils of the fleet when they are about to consume a planet.

Personally, I dislike tyranids for two reasons: first, there is nothing but battle when they are around, and I like my RPG's to be, well, RPG's. And my tabletop strategy games to remain as such XD. Second, never, ever allow an horde of genestealers to reach melee with the players. At least the ones in The Emperor Protects were capable of ignoring even Terminator armor's regular AP... and hordes can attack each turn to every enemy they are in contact with, and this ones give 1d10+14 of damage...

In my eyes it really comes down to the Synapse network, cause there's no way in hell to kill all the Nids of a Hive Fleet in square combat - maybe round combat but that's probably it.

Anyhow I think that alot of the examples mentioned are very good. You want to deal one massive blow to the synapse network, and then keep it off balance and target the strategic parts of the Hive Fleet. Reproductive creatures are good, the mass of lesser creatures can probably be ignored if they arn't in the way. Strange enough, the best option is probably to plan for one single battle or trap to take it all out. Trying to drag it out will only allow it to eat even more world and cause problem, or you'll have to burn a shitload of worlds just to keep it from expanding. There are some crazy ways like the Behemoth method but that may be a bit over the top for a regular game.

A plan that could work would be to draw the Tyranids towards a specially preapered fortress world, filled with Imperial forces dug in and waiting for the Nids, and then let the Tyranids attack. Having them bash themselves against the defenders should hopefully make the Tyranids gather themselves around this world and invest its biomass into it. When this is done, the fleet can attack and try to cause disarray in the Hive Fleet to break up the synapse network. If everything work as planned the Tyranids will fall asunder and not be given a chance to grow new large creatures for the synapse network. If all goes to hell, be ready to burn the whole planet to crisps.

That's how I would do it anyway.

You can also throw a large space marine homeworld in it's way. That seems to work ok.

Simple:

create a chaos cell.

-> rise a chaos cult of Slanesh, Tzeentch or Nurgle, Khorne would only feed the hive, well and would enjoy it...

-> throw the Planet and its vicincity in the warp

-> Problem solved.

Imperial solution:

-> gather more troops and wage a long war

-> see for chaos, as insanity and Corruption on the new Deathworld wil drive them there.

Eldar:

get your people, their gear, escape through the web, balst apart the ship.

so on...

Nids would be a cool device for RP if: Marines would know at least some fear, Nids were more than Locust on a field, well deadly, flesh devouring locust.

single purpose -> alien intellect beyond mortal scope -> doesn't talk much -> knows nothing of emotions only urges.

Even Orks provide more RP, nids you have horror... Problem mostly is so much horror no one enyos it or none at all. At least my experince.

Akil said:

Marines can know fear very well indeed... or at least their players can. You don't need a mechanical aspect to have a 'horror' feel to 'Nid games. 'Aliens' is a great example: The Marines weren't *afraid* of the Aliens in a 'scream and run away' sense, but they were certainly intimidated by their tactics, and surprised by them on a regular basis.

The key to good horror is to not concentrate on trying to scare the PCs with big scary monsters. Instead concentrate on scaring the players, by constantly surprising and second-guessing them and by putting them in fear for their precious character's life and Fate Points.

Akil said:

Somehow I didn't quite get your point. Surely players can't go hugging xenos with Tyranids, but that only means there is perhaps more RP amongst the Kill Team itself. Not to even mention the possibility of anyone else caught in middle of 'Nid invasion... Call of Cthulhu offers great possibilities for roleplaying and its not like the Great Old Ones will negotiate with you (or, for that matter, even acknowledge the tedious fact that you mights be something more than early breakfast for them).

On the scale of a Deathwatch campaign, I say target the synapse creatures. Kill enough of those , and this particular splinter of the Hive Fleet looses it's connection to the Hive Mind, and all the individual 'nids revert to dumb animals that just need to be mopped up. Of course, the Tyranids will learn from their mistakes and eventually return, but temporary solutions are about the best that Ultima Segmentum can hope for...

get a big jucy hive packed with tasty and expendable imperial citizens

fill buildings with explosives and promethum

let the bugs in

shut door

press detonate

Regarding Tyrannic foood supply issues.. as long as there bare seeding spore drops from orbital hive fleet ships and/or spore chimneys then even a barren world will end up lush with foliage as tyrannic organisms suck the mineral and chemical nutrients from a world turning it into plants which provide both cover (my 40k jungle trees are painted in my hive-fleets colour scheme to represent this) and will later be eaten by massive ripper swarms as part of the planets digestion. These plants would be a constant supply system for tyranid forces, perhaps even with weird gross fruit adapted to feed specific tyranid species. Even if the world is savedonce this has happened it will have become a deathworld where torn down forrests and jungles regrow overnight and all manner of deadly plantand animal life abounds.

Catachan is one such world, several of it's deadly lifeforms have been discovered to be tyranid in origin.

So early on a focus could be in trying to stop the tyrannoforming process from reaching the self-sustaining deathworld state. Not much could be done about this if there was a fleet in orbit other than to try hit and run baiting attacks to draw the fleet away from the planet/s to reduce seeding and reinforcing of troops by mycetic spore. Surgical strikes against spore chimneys would be crucial, with lots of combat against Hive Guard organisms with their impaler cannons and other tyrannic forces defending hive structures. Then exfoliating strikes perhaps done in bombing runs to destroy the frontlines food supply which would have to be frequent to overcome swift regrowth and propagation. If tyrannic forces were annihilated from the world thye war against tyrannic jungles and forrests would continue till they'd been rendered extinct.

Even without a fleet and after the destruction of any Dominatrix organisms and Tervigons many tyranid creatures are born from underground broodnest organisms. So destroying all of those would be vital to reducing tyranid numbers. Though very old background has Hormagaunts also laying eggs underground and reproducing independantly so waves of Hormagaunt births like Cicadas may turn up in bursts from time to time years afterwards.

If Capillary Towers and Digestion pools have already started forming in significant amounts and sizes and the mass ripper phase has begun while the hive fleet couldstill be denied the resources of the world through bombed towers, poisoned digestion pools etc the world would likely have little left but orgnic gruel. For even the valuable minerals and chemicals get harvested through this organic process.

But if a tyranid fleet is still in orbit pouring tyrannoforming spores onto a world and constantly reinforcing lost forces then i'd say the world would be just plain doomed unless something can be done about the hive ship/s at the centre of the fleet.

A world saved before turning to gruel but still a tyrannic death world would be a very interesting one to set missions on. It may have all manner of valuable heretical biology, a resource for exotic drugs and compounds for example, or it may still harbour hormagaunts or even genestealers and be frequently raided by dark eldar after beasts for their gladiatorial contests, attacked by khornate marines after the glory of battle, be fought over by schisms of inquisitors and magos biologis some wishing to wipe out the tyrannic life and others wanting to use the world as a giant lab for testing ways to kill the tyranids. And of course what Dagon has tasted Dagon may hunger even more for.. the hive fleets may yet return for another try at devouring the world in even greater numbers than before.

Inject it with the Obliterator Virus and sic the Grey Knights?

Oh by the way for anyone who has not read the latest tyranid codex...

TYRANIDS CAN SURVIVE EXTERMINATUS!

(at least a few can survive deep underground and emerge later)

Which could be a very nasty surprise to the Deathwatch and to players.

Yeah, but the Grey Knight codex is newer, so they'd be able to detect them and win somehow.

That's pretty much how it works, right?

Yup.

Plus we're talking Grey Knights here. They have the special rule " My Codex is Holier than Yours ", which basically says they can handwave any argument on the futile reason that it's invalid.

At least until a newer codex comes out.

I don't know why they don't just save ink with the things, do some artwork and write 'this army wins until [date]'

The Grey Knights did feature in Space Hulk in the 2nd expansion of course, one of my favourite artworks featuring a grey knight terminator with a stealer patriarch (broodlord) head in a jar kneelling before a bolter-equiped pulpit! So they did take Tyranids pretty seriously even though they are outside their daemonic remit. I suppose that when they found out one of the High Lords of Terra was a genestealer hybrid or brood brother it would have got them involved pretty seriously. Now if only GW would stop ignoring that cool old background and let us know more about the Genestealer War. I was surprised to see a reference to it in a single line in the novel Titanicus the other day which had me overjoyed as i had my adeptus titanicus titan legion be overtaken by a stealer cult years ago and there was a reference to a titan having fought in the stealer war so maybe Dan abnett had the same idea?

Of course as Deathwatch takes place before Ichar IV and the discovery of the true extent of stealer infiltration there could be great games built around the discovery of deeply entrenched stealer conspiracy as well as conflict between grey knights and deathwatch.

After all if the knights start hunting stealer infestations en masse they are likely to be treading on the watch's toes, not to mention likely considering the mass infiltration the watch's failure!

Its pretty impossible to say cathegorically that Tyrannids will survive Exterminatus as there are several very different weapon systems that can be use for Exterminatus:

Virus Bombs (Tyranid life forms might be resistant to the virus... or not)

Atmospheric Incineration Torpedoes (These are basically huge plasma bombs that will burn away the atmosphere of the planet and turn all of its surface into glass. Tyranid life forms might survive by digging deep)

Cyclonic Torpedoes (These things are basically huge melta bombs that are used to break the planets surface structure and cause the molten mass inside to come to the surface, turning the planet into volcanic nightmare. Digging yourself deep into the ground won't work unless the planet is inert with no or very limited molten core, in which case the Cyclonic torpedoes might not actually even destroy all the surface life)

Two-Phase Cyclonic Torpedoes (These things are cyclonic torpedoes that bury inside the core and blow there, destabilizing the whole planet and potentially ripping it apart. They are used against inert planets like Necron Tomb Worlds and the only protection against them is either to prevent the torpedo from hitting the planet or getting off the planet before it hits)

Siranui said:

Yeah! More artworks, less crunch!

I probably wouldn't use the Virus bombs as the biomass would be left and there is a possibility that the Tyranids could adept or assimilate the virus - scary idea. The other ones seems pretty ok to me though, in particilar if the Hive Fleet is close enough to the surface to be damaged when the bombs or torpedos are fired.