This article's a bit more about fluff and self-imposed army restrictions. I think that you can break down the Deathwing builds into four basic categories: 'Purist', 'Inclusive', 'Double-Wing,' and 'Fields some Deathwing Terminators.' Naturally, these titles are a bit arbitrary, but I'm not sure there are some definitive ones.
Note also that it's perfectly alright to use the Deathwing army list to represent just a first-company formation or first-company-heavy formation. Most chapters have their Terminators in the first company, as you have to be a hard core soldier among hard core soldiers to earn the right to wear it.
The Dark Angels and successors are collectively called 'The Unforgiven', though it's supposed to be a secret, self-inflicted title. In this context, the Deathwing are privvy to the exact reasons behind the unfortunate monicker (Hint: it has something to do with half their chapter siding with Horus, or at least appearing to. Just don't ask them why their floating space station has some planetary crust stuck to the bottom.).
The Deathwing Purist mindset focuses solely on what's in the first company. The list would be:
This is something of a limited list. I've touched on what you can get your Deathwing Terminators to do (and what they really can't). So, you have Dreadnoughts and Raiders to work with, or you can simply go all footslogging Terminators.
The shorthand version is that this is the most limited list, obviously. Raiders seriously cut down your model count, and if the enemy can kill AV14, you're screwed, pure and simple. Dreadnoughts can provide you with anti-tank firepower and/or long-ranged power, but there's still just not a lot of armor on the field.
Deathwing Purist also has the side effect of being finicky to build: all your points come in large chunks. Termies are 215-250ish a squad, Raiders are 250-65, and Dreads are 125-175. Tweaking a list gets to be a bit of a pain, at times.
I'm going to use 'Deathwing Inclusive' to denote armies that run Deathwing Terminators as their sole source of troops, but are willing to run just about any other option. This opens you up to:
As you can see, you suddenly got some more options. For the most part, these add some range and/or anti-tank punch to the list. Those that go for triple Vindicators often take the name 'Siegewing', for example, and can boast some actual anti-tank firepower and a fire magnet even greater than the Deathwing Terminator: the Vindicator. Predators can be long-range anti-infantry torrent units, or can be configured to be lascannon/autocannon bunkers. Speeders can mount multi-meltas and heavy flamers, and Dreadnoughts can get you lots of things.
Honestly, I feel that this type of a build grants you some serious flexibility; if you're determined to make Deathwing Terminators work as troops then I think adding in some supporting flavor isn't a bad idea.
AKA 'Death-raven', this refers to building your army exclusively out of Deathwing Terminators and Ravenwing squads. This means committing to either Belial OR Sammael as HQ choices, or both. However, going 'both' is bloody costly; that's upwards of 250-300 on HQ units. Given how costly you guys are on a model-per-model basis, I'd probably roll with an either/or proposition.
The strength of this army is in its deployment flexibility; it can combine the nasty scout move of Ravenwing Bikers with teleport homers and the Deathwing Assault. This translates to 'Man, where the hell did 10-15 terminators come from on turn one?' It's amazing for putting folks on the back foot right from the beginning.
The downside of double-wing is that you're going to have a low model count, and it takes lots of points to work. At least you get fast melta on bikes, though. I'd say, though, that the low model count makes the army hellishly unforgiving, if not highly difficult to work with. Still, its strength lies in a more unusual strategy. However, if folks are used to Demons, they'll have their own deep-strike defenses; you just have fewer guys, different CC, and better saves than they're used to.
Fields Some Deathwing Terminators
This build's minimal consideration is Belial and a couple Deathwing squads. Past that, it'll mix in basic power-armored schmucks, which is really what sets it apart from the other builds. I think this can help bolster the model count that you get with Deathwing, though. I think it might also help to bring in allies like Sisters of Battle and/or melta-bearing Inquisitorial Storm Troopers.
This build is likely the most flexible and wide-open, but it's also the most diluted scheme you can go with.
This article's a bit of a departure from my norm; it's more about theme and less about hard math and proof of what can work and what can blow up in your face. It's an interesting change of pace for me, and hopefully some variety in reading for you folks.
I'm curious to get feedback from readers on what they've seen the Deathwing in. This, of course, doesn't take into account various modeling themes, like Ron's Lustwing, or anything else. I mean, my own Deathwing project's a bit of a modeling theme; it's why they're taking so bloody long (and my quest to figure out a cheap way to get some lightning claws...).
Feedback is, of course, welcome.