The 40k Rivalries....

[Kakapo42]

Some great feedback here guys, and yes I think I misused the word rival, because the Death Guards rival would be Nurgle itself? But it seems like the Death Guard don't have that "ancient enemy". So how about another question, What are the Death doing now, what is their specific aim? An example would be that Ahriman and his cult are trying to gain access to the Black Libary of the Eldar, mentioned in multiple stories.
But what are the Death Guard up to, just chilling in the warp, or have they got a job to do?
Andy

The Death guard have the same job as all of Nurgle's servants: sow contagions, disease and decay throughout the material realm. To this extent they spend most of their time in Plague fleets travelling the Galaxy despoiling worlds, summoning daemonic hosts, spreading plagues and generally reeking havoc.

A thought occurs, since you seem to be looking for a cool enemy to match your Death Guard against, perhaps you could pit them against the Salamanders? From what I gather they seem to be one of the chapters that are especially concerned with the civilian people, so I can assume they'd be quite against the Death Guard spreading disease and whatnot, plus there's good 40kish imagery in the idea of fire battling cancerous rot and disease. Alternatively, another 'caring' faction like the Tau or even some Imperial Guard regiments could work as well, especially the Tau, as you then have the idea of high technology being pitted against primal plague.

[chriscrowing]

Dug into fluff (Lexicanum) and can't find any enduring Death Guard rivalries or a logical opposite/similarity in either the loyalist or traitor sides. Obv. as dour, despairing Nurglings, they should be against the Thousand Sons, to a degree - decay and transformation being opposites. in terms of the imperium, the IG would be their main rivals, espousing a similarly footsloggery military aesthetic.

[MooseOnTheLoose]

Some great feedback here guys, and yes I think I misused the word rival, because the Death Guards rival would be Nurgle itself? But it seems like the Death Guard don't have that "ancient enemy". So how about another question, What are the Death doing now, what is their specific aim? An example would be that Ahriman and his cult are trying to gain access to the Black Libary of the Eldar, mentioned in multiple stories.
But what are the Death Guard up to, just chilling in the warp, or have they got a job to do?
Andy

I believe they are pretty much just going around spreading the zombie plague... well Typhus at least. I can't say I really know of any other massive/focused goal of the Death Guard

[Gimp]

Cadians seem to have a particular hatred for Typhus and the Death Guard due to them spreading the Zombie Plague around.

Also Raven Guard also have a particular hatred for Typhus due to him destroying their flag ship the Shadow of the Emperor with the Terminus Est during the Drop Site Massacre

[Chrisb3]

Necrons (specifically Imotehk) hate Orcs.
Black Templars hate Necrons (specifically Imotehk).
That Eldar craftworld hunting Necrons hate Necrons.

The only two sided one there is Black Templars - Necrons, I don't think that the Orcs care about Necrons or Necrons care about Eldar.

[AlphariusOmegon20]

eldar, especially alaitoc v necrons
black templars v necrons (grand marshell hellbrecht)
biel tan v chaos (I think)
cadians v black legion
blood angels v chaos (sanguienius, nooooo!)
grey knights v chaos (obvious, cant belive no one has mentiond this)
saharnan 2nd(my IG regiment) v grey knights

It's Biel-Tan vs Orks

pg 16, eldar codex

The barbaric orks in particular are hated by the Biel-tan eldar, as they can spread across a newly colonised world as rapidly as a plague. There have been many accounts throughout Imperial history of the Biel-tan Eldar arriving to help a beleaguered Imperial garrison fighting against the Orks, only for the Aspect Warriors to turn on their erstwhile allies once the Orks have been destroyed.

Doc's right, it's Biel-tan that hates Orks. You're prolly thinking of Ulthwe and Chaos.

[Col. Tartleton]

Black Templars vs The Mutant, The Alien, and The Heretic

No Pity
No Remorse
No Fear
No Dresses

You Know Who You Are

[ReveredChaplainDrake]

Can you or anyone explain this one? (Raven Guard - Tau)

I think the Raven Guard participated heavily in the Damocles Crusade.

Did nobody mention Space Wolves and Dark Angels? That's about as "rivalry" as things get, at least by a literal definition of "rivals".

As for what the OP probably meant, sworn enemies, another really obscure one involves Night Lords and the Callidus Temple. I'm not sure if the Night Lords (specifically circa 13th Black Crusade) still care anymore, particularly after <i>Throne of Lies</i>, but it appears that it still holds some importance to a fairly large portion of the legion, dispersed as they may be, that a Callidus offed their primarch. <i>Void Stalker</i> also seems to suggest that Craftworld Ulthwe earned the Night Lords' enmity, though that may just be relevant to a specific random warband.

[stormblade]

Assasins don't kill people- bullets do.
And they are supplied by the Munitorum

[dæl]

Eldar v Slaanesh
Yarrick v Thraka
Grey Knights v SoB

I always figured Khorne v Tzeench, due to the hatred of psykers and magic / lack of subtlety. Why is it Nurgle v Tzeench?

[stormblade]

I always figured Khorne v Tzeench, due to the hatred of psykers and magic / lack of subtlety. Why is it Nurgle v Tzeench?

They are philosohical opposites, tzeench is change and hope while nurgle is stagnation and despair.

Khorne is opposed to tzeench because he dislikes sorcery but tzeench does not see him as a rival.

[Ragnarfan_12]

the Space wolves vs the thousand sons are deffenetly rivals the SW destorys TS homeplanet and in turn TS attacked Fenris also landded during a meteror shower and started an uprising They also almost destoryed the Space wolf chapter ... idk seems like rival kinda thing to me...

[Gorbad Ironclaw]

I always figured Khorne v Tzeench, due to the hatred of psykers and magic / lack of subtlety. Why is it Nurgle v Tzeench?

As Stormblade said, it's because the Chaos Gods are supposed to be a bit deeper than the cardboard cut-out presented currently. Tzeentch is about aspirations, hope, change, planning, new and better, Nurgle is about decay, despair, stasis, hopelessness, giving up, accepting the inevitable.

(Sadly, it also means that the Thousand Sons are a much better fit for Nurgle than they are for Tzeentch...)

Khorne might think some of Tzeentch methods (magic/psychic powers) are weak but he isn't opposed to the core principles of Tzeentch. In fact, the two of them are the others most frequent ally because together they are stronger than any combination of other Chaos gods.

[Shadow Lord]

Mmm...I think all 4 Chaos Goad are rivals( in the sense that they all try to achieve the same goal, but they use different ways) from each other...they all want supremacy by any means (even allying with other Gods). Space Marines vs Chaos Space Marine aren't rivals, they're enemies! This is definetly not the same thing...
Iron Warriors - Imperial Fists started as rivals but ended as enemies, etc...
Death Guard are essentially doing what all other Chaos Leagions/minions do...work their asses off in favour of their patron God by doing His Will...and ofc trying to survive inside/outside the Warp!