Daemon HuntersDaemon Hunters are, in my 'umble opinion, a 'gimmick' army - but man, do they ever have a TON of gimmicks! Just like Chaos, however, there are broad sweeps of armies which are chosen either because they're dramatically effective or because they're dramatically fluffy.
First of all, I need to discuss Inquisitors. These are, basically, RPG characters put into a wargame, and most players treat them this way - which means you can't predict what they're going to have beforehand.
Some like the close -combat approach, and with a Daemonhammer, some Combat Servitors with Power Fists, the right psychic powers, and a couple of Acolytes to suck up spare wounds, they can be deadly against Daemons, and hardly less so against Space Marines - but such a squad is fairly expensive, and most DH players prefer to leave the close combat to the GKs.
There's also the proven shooty approach, with an Inquisitor armed with a Psycannon, some Heavy Bolter Servitors, and a Mystic to make sure they can take a free potshot at deep striking enemies. This one is more common because it's still fairly cheap, is quite deadly, and serves as as substitute for Devastator squads - but it also takes up an Elites slot. Still and all, I'd use it if I had a DH army...
But don't forget that Inquisitors are hardly tough for the points some players load into them, and (for the most part) they're hardly troublesome to a space marine player... a Chaos player hates 'em, but that's neither here nor there is it?
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mixed, no allies army will generally be bossed by an Inquisitor Lord or Grey Knight Grand Master, but it'll have at least one Inquisitor in it for the ability to take Assassins. The main troops will be Stormtroopers configured for short-range firepower - probably with twin plasma guns in a Rhino, and the Veteran having a Thunder Hammer.
Elites will probably be an Inquisitor configured in a shooty unit (the most efficient and cheapest way to make them work), an Assassin (Callidus is favored for the head-fragging effect, but there's a cheap tactic with the Culexus that I cover in more detail later), and a squad of GK terminators if the GK Grand Master doesn't already have an escort. He may also have some Death-Cult assassins - those guys are a suicide squad, and he'll treat them as such. I'll cover Daemonhosts in a little bit, under the Radical Force. Fast Attack - well, there's only one option for a no allies army and that's the Teleport Attack squad. Heavy Support could come in the form of a Land Raider Crusader, a GK Dreadnought or two, and if he's a gambling man or is very tactically minded, a cheap Orbital strike.
I'm going to diverge a moment here and explore two points. Grey Knights are good at close combat, to be sure, but what they should be truly feared for is their ability to hose down squads. With Stormbolters on all of the regular troops and two Psycannons, they have a deadly rain of fire they can direct anywhere, and it's sometimes difficult to see them with their special rule to return the fire. GK squads are deadly on the move, but expensive... as I'll discuss later.
Second of all, the Culexus assassin. It has a weapon which gets +1 to its shots for every psyker within 12". Every GK Justicar, Brother-Captain, Grand Master, and Inquisitor all count as Psykers - which leads some players to use the Culexus and keep his army as close together as possible. It's an oddball thing, but one you're more likely to see in a mixed, no allies army than in any other one.
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mixed, Inducted Imperial Guard is actually quite lethal. The fluff-minded will lead it with an Inquisitor Lord, the ones with a bent towards winning will field a GK Grand Master - the cheapness of the IG will counteract the expense of the GKs. For Troops, remember that he has to have two Troops choices of DH before he can pick any allies, but that's only as expensive as two small squads of Stormtroopers. For IG allies, he'll want relatively large platoons - figure on at least 3 squads in each platoon, not counting the command squad. Lascannons and Plasma Guns are standard kit for IG, at least according to the way this player will probably pick 'em. If he knows anything about IG, it's entirely likely that the small 5-man command squad will be equipped with 4 Flamers - that many flamer templates will kill even Space Marines. Or he may not get them anything at all.
For Elites, see the above section.
For Fast Attack, figure on a Sentinel squadron - because of their ability to deploy even in Escalation, move fast, carry heavy weapons, and general cheapness, they're a no-brainer choice. He may have a Rough Rider squadron as well, but those are mostly for a surprise effect. They really aren't too great, even with Hunting Lances, but they can gallop around as last-minute objective grabbers. However, as proved in World War 1, horses don't like machine guns - one round of fire should reduce these to hardly dangerous levels. With the numbers of the IG brings an impo
Expect to see a Leman Russ added to this army - with the only (reliable) Ordnance weapon available to the DHs, it's another no-brainer. Probably with heavy bolters all around, too, just because it's relatively cheap.
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mixed, Space Marine Allies force is generally the exception rather than the rule - because most DH players like the Grey Knights, the fact that having Marines excludes the GKs turns a lot of players away. The exception to this is the Radical Force that I'll discuss in a bit. The tactics for such an army aren't clearly defined, but expect to see Landspeeders, plenty of Tactical Marines, lots of Assassins, and maybe even two Inquisitors.
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Radical Force is someone taking the roleplaying aspect of the Inquisitor to the farthest level - and adding Daemonhosts to his army. Daemonhosts are, quite honestly, dead hard but very random - one may be able to move and assault 24", another may be able to drop an S3 AP2 Ordnance blast... ask him to roll the psychic powers in front of you and study which Host has which power. A Radical Force is quite likely to include Space Marines - thus adding some hard shells to the army. More likely than not, this force will be oriented towards getting in close and getting personal - expect to see Assault Squads, Deathcults, and plenty of Space Marine heavy support.
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pure Inquisition force is a downright oddity. I don't think I've even HEARD of such a thing. For troops, it would have plenty of Stormtroopers in Rhinos geared towards short-range Rapid Firing, and, uh... has anyone seen a force like this? Help me out here! My Omniscience has failed me!
People who play
pure Grey Knights don't expect to win. Seriously. They play because they like the fluff of the GKs, they like the models, they like the challenge, but they never, EVER go in expecting to win. Planning to win? Yes. You can expect a low model count, expensive but deadly units, and not much else. Follow the doctrine of reducing his scoring units to a maneagable level, blow up any heavy support vehicles he may have, avoid close combat with his Terminators, and you shouldn't have any problems at all. You'll lose some models to concentrated storm bolter fire, but it isn't really all THAT much to worry about...
EldarSome, SOME of what I've said about the Dark Eldar also apply to regular Eldar, but overall the Eldar are much more durable and more versatile
Also, the problem with the Eldar codex is that approximately half of the units listed, and all but two of the heavy weapons, are pretty much useless. I may give props to people who include well-modeled Guardian Jetbike squads or Fire Prisms in their armies, but I won't include such wretchedly awful units in any general tactica. Just remember, they're overpriced.
First off, a short lecture on Wraithlords: You're going to see at least one, more likely two, possibly even three, in any competitive armies. They attract fire away from the softer bits of the army, they're very tough, and they're very nasty in close combat: All things that are a bit lacking in most of the Eldar list. Lascannons, plasma guns, and (actually) Power Fists are your best bet. Remember, it only has three wounds and a 3+ save - sure, that's tough, but it's not invincible... don't be afraid of it to the point that you fire ALL of your guns at it because those Heavy Bolters are much better directed at other parts of the army, but don't discount it either. It is, after all, very slow...
Next, Farseers - these guys are almost infinitely deadly. With the ability to use two psychic powers a turn, one that lets a squad nearby reroll any failed saves, one that lets him snipe out a model of his choice, a third that is a pinning Ordnance blast, and the last (and most lethal) that lets a nearby squad reroll any failed to-hits, this guy is a primo threat - but he supports OTHER squads, rather than being a huge threat by himself. Figure out what job that the other player has given his Farseer, and crush his ability to do that job - kill the squads he was supposed to Guide, keep your soft models out of the 18" Mind War range, etcetera.
There are six (or seven) potential armies in the Eldar purvey, and I'll cover them in order of descending popularity.
Ulthwe armies are the most popular, for several reasons. One is the ability to load up on cheap Guardian squads and stick plenty of Starcannons in them, another is the very, VERY tough Seer Council, a third is... well, I guess that's about it. This army is pretty hard for a Space Marine army to beat, to be honest. Fast attack is likely to be more Vypers with Starcannons or possibly Brightlances to hunt down tanks, heavy support is going to be Wraithlords with maybe a squad of Dark Reapers or War Walkers that are Guided by one of the Farseers. Seer Councils will likely be able to snipe out anyone they want with Mind War Augmented out to a truly dangerous range. He'll also quite likely have Warlocks detached from his Council to protect the Guardians with an ability that gives them a 5+ cover save - just the thing to help out against Bolter fire.
My recommendations: Don't waste ANY firepower on the Seer Council if you can help it. Concentrate on eliminating one squad of Guardians at a time, starting with the BS4 Guardians. Make War Walkers, if he has any with double starcannons, your TOP priority - they're very expensive, very frail, and very lethal. If they get a chance to fire at a squad of Marines, that squad is toast - make sure they didn't die in vain. Wraithlords can be ignored for a while in favor of whittling down his numbers; once they get close, THAT'S when you want to blast them with all you've got.
A subsect of Ulthwe is the
Ulthwe Strike Force - though honestly, this army isn't much of a threat. One failed Ld test and the squad never returns. Most of the army has to start in reserve. Sure, they shoot better - but they're also more vulnerable.
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Codex Army is for someone who likes shooting, but also likes Aspect Warriors - a variable force. Expect him to have enough shooting to tie you down, but be using close combat to finish the job. With the death of Rhino Rush also came the death of Serpent Rush - but still, you shouldn't discount even the foot speed of basic Eldar. Depending on which way he goes, my comments about any of the armies here could apply - read those notations and once you see a Codex army, use those notations accordingly.
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Altioc army depends on Rangers and Pathfinders to mess with you, then gun down your squads with their eldar sniper rifles. "Sniper rifles?" you sneer, "I ain't afraid of those!" Remember, Eldar rifles have AP1 on a roll of 6 to hit - and Pathfinders get that on a 4-6. Enough shots could take down ANYTHING. Cheesy players will take the three Wraithlords - but more moderate players will balance things out and max on their Disruption rolls. Striking Scorpions are the most likely aspect here - the ability to Infiltrate coupled with close combat ability and the durability that the Rangers lack make them a no-nonsense choice. Swooping Hawks are also likely - watch for their Exarch with the Sustained Assault power.
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Biel-tan army is, in my mind, the oldschool way of playing. Aspect Warriors are the bread and butter of this army, with Guardians, Rangers, and Vypers pushed to a backseat. Also, it's the only army where you're fairly likely to spot an Avatar - the Avatar isn't so scary by themselves, but they support other close-combat Eldar very nicely. Take it down with Heavy Bolters - it may be T6, but with a measly 5+ Invulnerable save it won't last long against sustained fire. Don't waste too much fire on it, however - regular marines can and will kill it in CC eventually.
Biel-tan is bent on getting close in and dirty as fast as possible - quite a contrast to the other two armies! With lots of Howling Banshees and Striking Scorpions available, you'd best hope to be quick.
A quick rant on Aspect Warriors - each Aspect is spectacularly good at one job, and pretty darn bad at everything else. The most popular Aspects, however, are close-combat oriented - Howling Banshees and Striking Scorpions. Of the two, Howling Banshees are the bigger threat, but Striking Scorpions are more likely to live - a player with both is gambling that you'll shoot down the Banshees and leave his Scorpions alive. Fire Dragons are good at both Terminator and tank-hunting - don't give him an opportunity to do either with them. Few people use Dark Reapers these days, what with the popularity of the Guardian Starcannon platforms, but if you see them, KILL THEM - they're brutal against Space Marines.
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Iyanden Craftworld force is almost the antithesis of Eldar forces - very slow, very tough, and very low model count. You'll probably see three squads of Wraithguard and three Wraithlords - but for this army, it's actually FLUFFY to have that many Wraithlords! He'll likely have close combat Aspects to support his Wraithguard, and the army will be led by a Farseer - he needs those Warlocks to make sure his Wraithguard go where he needs them. Wraithguard are very, VERY effective against both vehicles and heavily armoured troops - I destroyed two Monoliths with a single Wraithguard squad in a game. However, they're not good at CC (despite being tough) and against hordes they do very little good.
The last (and least-used) force is the
Saim Hann strike. You'll see lots of Vypers, lots of Jetbikes, and not much else in this kind of army - but honestly... it isn't that much of a threat. Anything in this army has to be mounted in a vehicle or on a jetbike, so that raises the price of the average model to quite high numbers. Generally, it's a fluffy/modeling army rather than a serious one, but that doesn't mean it can't be very fast and very nasty.
Finally, one last word on Eldar and Dark Eldar: People playing these armies are liable to be very experienced. I don't meet many n00bs who play with either; if they start with those armies they set them aside or sell them in favor of more durable 3+ save armies. After all, it isn't as if either of these armies get ANY FRAGGING SUPPORT from GW...

So only veterans are interested in them still. That means you have to be just as good to beat them - or, at least, to tie them.
"I don't think of them as loopholes. I think of them as the special rules that designers include to reward dedicated players like me."
- Brian, Knight of the Dinner Table
"As bizarre as it seems, GW simply does not believe it is in the business of making games. It sees itself as a model-maker only. The top brass, the guys making all the business decisions, and even the games designers themselves, have all openly said that the games exist only as a means to push the models. (Why they refuse to see how the game can push the models is beyond me. It's what worked on me.)"
-Number6