There is, of course, a flip side to every coin. While it’s perfectly legitimate to select one’s Allies purely on the basis of strategic and tactical advantage, there’s also the Narrative and the Forging thereof, to which 40K.6 is as committed as a jeweller who sells wedding rings to stalkers.
Let’s say, for instance, that you’re a Chaos player, but more than just a Chaos player; you’re a Chaos player interested in representing the gradual rise of a planet from the drudgesome mundanity of the everyday Imperium to the glorious heights only offered by the very Darkest of Gods. Yours is not the Traitor Legion or even Renegade Chapter army embodied by the conventional Chaos book, though those Legionnaires are involved for sure. However, they’re involved as instigators, as advisors, as demagogues and as living icons to the lesser worshippers of the Great Powers. Your army needs to look like an Imperial army with a few Chaos Space Marine ‘advisors’; primarily, this will be an Imperial Guard army, albeit one with limited elements of the command structure maintained. As I mentioned long ago when blathering on about how counts-as was the best way to do Chaos under a boring, limited Chaos book, the Traitor Guard army is probably going to be light on Commissars, perhaps quite heavy on Priests (of Chaos, yo) and Psykers, and could legitimately squish in a few Ogryns as big spitty mutants if you were that way inclined. The posh stuff like Storm Troopers and Deathstrike Missiles would probably have remained loyal, but that leaves plenty of room for Veterans and Hydras and other, well, more orthodox Guard stuff. The Chaos allies for such a Traitor Guard force would probably comprise a couple of small Marine squads, or even Cultists (civilian members of the Chaos conspiracy, distinguished from the Guard by their poorer equipment), with maybe some Chosen or Cult Marines in Elites as the Traitor Legion masterminds of the affair. The Allied HQ seems to cry out for a Dark Apostle – the conspiracy’s demagogue and grand architect – and it’d be tempting to take Chaos Spawn and a low-key Heavy Support like a Vindicator or something. Possibly a Defiler, depending on how far gone the conspiracy is.
OR there’s always the player who regularly faces off against Grey Knights – perhaps they’re a garage gamer who mainly plays with one or two close pals – and wants to justify the Grey Knights’ presence against any of their varied armies. Daemon allies are tailor-made for these people. A Greater Daemon, the terrible power possessing a member of their army or being summoned into play by its loyal associates – let’s say they’re Orks, actually, Orks who’ve gone a bit Khorney round the edges as was always a risk in the Rogue Trader days. That means a Bloodthirster, and correspondingly Khornate choices from all the other slots offered by Daemon allies; there’d have to be a great many Daemons to justify deploying more than a squad of Grey Knights, wouldn’t there? The Ork force, meanwhile, probably comprises Stormboyz of Khorne (yep, they’re a thing), and… actually, could probably get away with more or less anything provided it looked right.
OR how about the Tau player whose Ethereal harbours ambitions of bringing major alien races into the fold? Aliens like, say, Eldar Exodites, whose throwbacky ways lead to lots of dragon-riding folk (smaller ones as Jetbikes, larger ones based on the High Elf kits as the various grav-tanks – not sure how a Falcon would work, maybe people riding on a harness or howdah or something) – or Corsairs, maybe, a force without much in the way of heavy equipment but big on Harlequins, Storm Guardians and the like – or even a full Craftworld, ravaged by war, whose few survivors have accepted the Tau’s offer because it’s better than diminishing into ineffective nothingness.
Of these three I think I like the Tau and Eldar idea the best, and not just because it’d give a creative modeller the excuse to produce squads of dragonhawk-riders. I think I like it because it has an implicit narrative, a grabbing question – how did these guys get together? – that can be answered on an aesthetic level without necessarily offering every opponent a copy of your fifty-page justificatory fan-fiction. If you saw a whole bunch of Eldar Exodites whose support weapons had a hint of Tau technology about them, with a few Battlesuits and Fire Warriors and an Ethereal lurking around the edges, that says something quite different to a well-equipped and substantial Tau army lacking Kroot or Vespid but sporting instead small, ragged units of Guardians and Aspect Warriors, maybe with a few well-modelled injuries and a ghost-warrior unit or two.
It’s that sense of immediately, visually, viscerally making sense that’s guided my own approach to Allies. Though I have several favourite Chaoses – the Fallen Angels, the Night Lords, the Word Bearers, the Red Corsairs, and that renegade Chapter the Lightbringers with whom I shall one day see fit to do something even if it’s just build an Epic army for them – the Chaos which makes the most immediate and obvious sense as allies to Necrons is distinctly more ferrous in flavour.
Iron Warriors don’t just share a quick-and-easy colour-scheme with Necrons, which creates an immediate visual tie, although they do and it does help. They’re obsessed with impenetrable fortresses (“a challenge!” they might well say) and ancient, eldritch technologies of personal transformation, things which a Necron Tomb World offers in earnest. It’s not implausible that a force of Iron Warriors might come into possession of some Necron technology – powerful tools represented perhaps by a well-chosen Chaos Artefact or two – and, being curious as to its origins, seek out the manufacturers in search of more.
Now, the average Necron Overlord could and presumably would obliterate members of the lesser races for even trying to appropriate their technology – unless of course there’s something stopping them, something preventing them from deploying their full might and majesty. Something, perhaps, like a Tomb World that’s only just woken up; a Tomb World orbiting a dying sun, short of power; a Tomb World frozen in its long journey through the void and now thawing out, with ice and flood and all that sort of thing doing what they do to machinery and leaving major systems less than entirely operational.
Such a Tomb World might see reason in forming an alliance of convenience with one set of interlopers against the prospect or immediate threat of others, particularly if those interlopers can be fobbed off with damaged or dangerous equipment and especially if said interlopers have some thoughts of their own on the fusion of meat and metal. It’s not inconceivable, I feel, that some Necrons are interested in the possibility of reclaiming their flesh, or at least with experiments and modifications to the process of biotransference. It’s also not inconceivable that members of the Iron Warriors Legion, witnessing the warping effect that Chaos has had on them, might adopt bionic replacements for mutated parts, might think Ahriman was on to something with his desire to rid his Legion of mutation, might in point of fact be interested in the technology of biotransference for its own sake.
Ah, but I’m getting into fan-fiction again, aren’t I? And this is about making the alliance plausible and palatable on an immediate and shallow level, smoothing the ruffled feathers of the suspicious opponent who is ever on the watch and has an armoury of slurs for those who Do 40K Wrong in some way, creating something to which more reasoned colleagues in play might say:
So, let’s talk about unit selections. Its being an Iron Warriors army mean that the more daemonic aspects of the Chaos forces should be less in evidence; Daemon Princes are a bit too powerful to waste their time on being Allies, while Spawn, Possessed and Warp Talons feel a bit too daemon-ish. Cult troops are (to my regret) probably ruled out too; while they could be acceptable in a pure Chaos force, in which our Iron Warriors have collaborated with members of another Legion, they dilute the theme of a contingent allied to some other army. Everything needs to pull together and look, well, Iron-Warrior-ish, and while I’d love to do some Berzerkers or Plague Marines in rusty iron or some siegey Noise Marines in the Legion’s colours, I don’t know how well that might go down. To be on the safe side, let’s leave the Cult Marines out for now.
Marked Troops are probably okay though, and I’m not just saying that because I want them. The Mark of Nurgle, affording a Toughness boost, is easily justifiable; bionic parts! The Marks of Khorne and Slaanesh correspond partially to known combat drugs of the forty-first millennium; Frenzon and Slaught respectively. As for their standards, well, combat drugs need a dispensing apothecary or chirurgeon, possibly with that nifty backpack (though goodness knows what I’d do with the Fallen ones). The Nurgle one is a bit more awkward, so let’s not go there and save the banners for the drug-addled units, eh what? Undivided units packing an Icon of Vengeance could likewise have a backpack ornament, a comms. array or something; it’s no more ridiculous than the spike with the impaled heads on it, which was the norm the last time I was building Chaos Space Marines (2004-2008, if you’re keeping up).
What else? The Iron Warriors are not known for their bevy of Fast Attack forces, although how much of that is owed to pernicious influences from That One Codex Which No Chaos Player Can Get Over I’m not sure. Even Raptors feel like pushing my luck a bit; I think either a Heldrake (Daemon Engines being the only Daemonry I’m willing to countenance in an Iron Warriors army) or Chaos Bikers equipped as wall-breaking meltagun platforms would do the trick. In Elites we have Terminators, Mutilators and Chosen making their appearances; Chosen are especially appealing as I’m of the opinion that Traitor Legionnaires should all be elite hard cases, and I’m strongly considering a build in which all the actual Iron Warriors are from outside a Troops section filled with the Cultist slaves who dig trenches and charge enemy gun-lines to test their fields of fire. In Heavy Support, I would suggest that pretty much anything goes; Forgefiends and Maulerfiends fit the army well but are a bit big for Allies, and so I’d be more likely to go for the old standby of the Obliterators or possibly a Predator or Vindicator. For HQ, of course, it pretty much has to be the Warpsmith, doesn’t it? Well, maybe not; a powerful central figure is certainly called for, but given the pursuit of biotransference I’m wondering if I couldn’t shift a Biomancy-focused Sorcerer or even a Dark Apostle?