Although not actively promoted by games workshop in recent years, there is a large amount of animosity amongst the different chaos gods.
Everyone knows there are 4 main chaos ‘marks’: Khorne, Nurgle, Tzeentch and Slaanesh. Even in the current Hordes of Chaos book and to the same extent, in the beast book, there are restrictions on which marks you can take with each other. For example, you cannot take a god specific general and then have other marks within your army. However you could take an undivided general and mix marks freely dependant on other restrictions.
With the new daemon books coming out, this has appeared to have dumbed down even more, with the ability of mixing units of different chaos denominations, and to some extent, requires you to take different god options to compete against some lists.
Judging by the forums, this has caused quite a few burst blood vessels.
Hopefully we can go back in time and see how this all started, and then jump back into the present and see what this all really means within the new world of warhammer context.
Back in the day, and please correct any of my mistakes, two books were written called Realm of Chaos: Slaves to darkness and Realm of Chaos: Lost and the Damned. Whilst you don’t need to know too much about these books except they cost a lot of money on Ebay in mint condition and they are very out of date rules wise, they do provide a LOT of fluff, pictures, ideas and information relevant to people obsessed with chaos.
The two books were divided roughly by gods, with slaves to darkness containing information on Slaanesh aqnd Khorne, lost and the damned containing information on Nurgle and Tzeentch.
Although each god, mark, faction of chaos hates all other factions of chaos, there are specific arch enemies. Tzeentch hates Nurgle and visa versa. Slaanesh hates Knorne and visa versa.
Looking at each god and what they stand for goes some way to explaining that.
Nurgle is the god of plague, disease and decay and…..hope. We’ll get to that last one later, but for the moment, we’ll stick with the first three. This is in obvious conflict with Tzeentch, the god of change. In simple terms, Tzeentch evolves and changes, nurgle decays and ages.
The same eternal conflict exists with Slaanesh and Khorne. Khorne exists to kill, excel in combat and finish lives. Slaanesh believes in a lifelong pleasure and fulfilment.
A smaller obvious rivalry is slaanesh and nurgle, due to the whole beauty/ugly angle, and khorne/tzeentch due to the whole magic/anti magic angle/.
Looking at it this way, the most obvious allies are Nurgle and Khorne or Slaanesh and Tzeentch.
I think thats about as much detail we need to go into here, as plenty of info can be found on the web.
Which brings me to my point, how do you feel about mixing and matching? I personally would endevour to take only Khorne and Nurgle, but the idea of a slaanesh mortal army is starting to entice me.
With the new Hordes of Chaos list being put out in the next few months in white dwarf, I think I’ll need to consider my daemon and mortal armies very carefully.
Warphammer 
Back in the late 80’s(87-90 I think) I was running a WHFRPG game. I picked up Slaves to Darkness when it came out and that greatly enhanced our game. In fact since the main plotline the heroes were following was to uncover and destroy a plot of chaos it added essencial elements. It wasn’t a very good book – it was kind of scattered. The “gifts” of Chaos were often not very compelliing and the randomly generated Chaos weapons were often not very strong. Sure you could get lucky and have something very powerful come out of it but more likely than not it was a random and confused thing.
That said we did enjoy the fluff bits and we did end up ignoring the tables and just mining from it good ideas. A few years ago I put mine up on ebay along with a lot of other things I didn’t want. I was shocked when it went for nearly $80. I think I had paid $20 for it. It was still in excellent condition.
As for mixing and matching – they should have stuck with the main story line. It jives well with current events which we all read in the news where one group of people is actually divided against itself. That can refer to just about anything from Democrats to Muslims to African politics. It certainly made Chaos more interesting.
Great blog. I noticed I was on your blog roll so I am adding you to mine. Glad to have come across it today!
–Pete
Hope? Nurgle? I hope you touch more on this, I’m quite intrigued. The only way I can parallel hope with the rest is the hope of release as one wastes away with a terrible disease/affliction.
Suitably twisted if so, but…?
Ah hope, I said I’d touch on it and never did. Watch for my next post.
@Pete, glad you like the blog. I’ve been offline for a few weeks while I move, but now I’m back on it.
I just bought a fairly good copy of lost and the damned from e-bay for £60 ($120) as I have no idea where mine went.
I know what you mean about it being all over the place, we never used them for gaming, but did exactly what you did and used it for our WHFRP inspiration.
Frankly, I’ve never played a “mix and match” Chaos army, preferring the thematic approach of just having one Chaos God. Even in my Wordbearers I tended to just pick daemonic units from a single army in each army list.