Greetings all,welcome to another post in my Army Building series - I know I've not done many of these recently, but believe me I've been plenty busy!This post is another in my list building section of the series and kind of follows on from the formations and detachments article I wrote a while back. What I'm going to really focus on here is the factions specific detachments, so things like the Necron Decurion, the Adeptus Astartes Gladius Strike Force etc.First I'll be looking at the principles of making the most of these formations, then I'll take you through a couple of worked examples I did at the weekend when I had the house to myself and had time to think it through properly, rather than snatching 5 minutes to quickly scribble a list as is usually my method these days. Ok, so the faction specific detachments come in a fairly standard format now, they've been around plenty long enough to settle down nicely.In terms of force organisation, you have three sections. Core choices, Command choices and Auxiliary choices. These are largely made up of formations but may also include unit entries such as the Thunderfire Cannon in the case of the Sternhammer Strike Force, or the Drone Net in the case of the Hunter Contingent.You will usually be required to take at least one core formation, which then gives you access to a number of auxiliary formations, and command formations.We'll set those aside for now however, because the first principle of building a list using these detachments is understanding what they are supposed to do for you, and hence why the article is titled as leveraging these faction specific detachments. We need to truly understand what the benefits are of taking an army fitted into these restrictions to make the most of it.Each of the detachments, as with formations, comes with its own specific command benefits, ranging from things like granting access to doctrines in the Gladius Strike Force, to giving your units bonuses to their shooting for ganging up on the enemy in the case of the Tau Hunter Contingent.Ok so the above part is slightly tongue in cheek, but there's method behind it, believe me.Let's look first at the Gladius, as its benefits don't necessarily point you directly at taking a particular type of unit, as some of them can. It's also one where the restrictions on unit choice set a good example of what I'm talking about.First up, the Gladius allows you to enact each of the Combat Doctrines once per game. These doctrines directly benefit the units in your army and make them work better, with each of them affecting all the relevant units, but giving a specific bonus to one type of unit. Now in terms of army selection you don't need to do a huge amount with them, as the core choice for the Gladius requires you to take certain units, most of which are affected by the doctrines (only the land speeder squadron doesn't get the benefits of the assault doctrine). It's obvious however, that the command benefit was written specifically with the demi-company in mind, as there's so much synergy between the units required in the demi-company and the doctrine system.The second command benefit of the Gladius is the one that causes so many people irritation. If you include two demi-companies in your Gladius (ok, so a full company) then you get basic transports for free. As a maximum benefit, this means you could pick up around 550pts of transports for free. You still need to pay for upgrade armaments on them, but even so, those transports will be objective secured thanks to the formation benefits of the demi-company anyway so you can make a veritable nightmare of claiming objectives for your opponent. Imagine for example 10 drop pods hitting the table (just don't imagine painting them or you'll burst into tears), each disgorging 2 combat squads of objective secured marines - that's giving you 5 obsec units. You should pretty much be able to guarantee your opponent never scores an objective in the whole game if you go first. When you look at the combination of special rules the Gladius gives to you therefore, it becomes clear that it is intended to facilitate a particular style of play - balance in your forces, through very specific unit selection options, and a total focus on the mission objectives. In this regard the Gladius then rewards very specifically the use of maelstrom mission cards that require securing of objectives, and a focus on the part of the player using it to score those same cards. Surely that's obvious though? Well other faction specific detachments lead you down a different path, enhancing the damage output potential of your army rather than focusing on objectives. It;s also why the Gladius is the 'basic' faction specific detachment for the most all round safe faction in the game - it's teaching you how to win the game, without stating this is how it's done.A little deeper thinking illustrates the point even further - since it is fairly reasonable to accept that given free choice, many players wouldn't take the units required by the demi-company as they are some of the units that have lesser damage output and are more generic, the Gladius further balances things out by giving those units little boosts to their effectiveness.Ok so having attended the Greetings from the Warp doubles event and having been schooled in our second match on how to select an army to win based on leveraging the army selection rules (in a 1600pt list we faced 3 Riptides, a unit of Grav Centurions ignoring cover, and a Fire Raptor), I set about creating a much tougher and more effective army than I had previously planned in my comparison of the CAD and Sternhammer.I looked in more depth at the rules for Pedro Kantor therefore, since I know he's a pretty good force multiplier anyway, and seeing them again in the light of my experience and the new marine psychic powers I figured I'd see what I could do to build a force around him. He can't be taken in the Sternhammer Strike Force, so I looked at the possibility of using the Gladius instead, and started from first principles, ditching my preference for using a knight and looking to write a solely space marine list.Pedro Kantor is a Command choice in the Gladius Detachment, and he grants very specific benefits to models in his detachment, namely +1A within 12". He also brings preferred enemy (Orks) to the table, though that is rarely relevant in my games as it's a long long time since I've played against them. He makes Sternguard in his detachment objective secured too, so that's certainly something to bear in mind. There are therefore two very particular selections that he'll provide a benefit to - first is a unit or units that need to be in combat, as boosting the attacks of such units, combined with the option to re-roll '1's from the assault doctrine is pretty cool, and the second is a force heavy on Sternguard. In fact, if you took a 1st Company Task Force solely consisting of Sternguard as the auxiliary choice in a Gladius, Kantor himself would be the only unit that wasn't obsec!I do like to ensure that I've got all the bases covered in my lists though, and that includes taking a good strong combat unit. Kantor himself is pretty nasty in combat, but his particular benefits obviously lend themselves towards pushing a combat unit to the max. What better unit is there in the space marine codex in that regard than the Honour Guard? It's very fluffy anyway, since Kantor is a Chapter Master, and the Honour Guard are also a choice available in the Gladius Strike Force Command selection. Combine Kantor with the Honour Guard and a Chapter Banner, and you're starting to put together a very capable assault unit, most of the members will be putting out 6 attacks each on the charge (2 base, +1 for an extra melee weapon, +1 for charging, +1 for Kantor's bonus and +1 for the Chapter Banner) using power weapons, added to Kantor's own attacks (4 base, plus 3 of the above bonuses) and you've got a unit that starts at 26 attacks for the 4 basic models and only gets more hideous from there. This unit also leverages the ability to use the assault doctrine for a turn, granting those attacks the ability to re-roll any '1's.Incidentally I did originally consider pairing Kantor with the Centurion Siegebreaker cohort to boost up their number of attacks to a level where they will start to cause significant damage, but the difficulty of accommodating that formation in a Gladius alongside a demi-company put me off, the balance was all wrong.I had no choice over the core formation for the detachment, so I looked at what benefits I could use from the Chapter Tactics and Gladius Strike Force to build a tough core.3 Tactical Squads are a quite literally a must-have, so I started with them. The demi-company rules make them objective secured, so a tough transport to go with them would multiply their effectiveness on the field and force my opponents to have to clear the transports as well. I'm really liking using drop pods at the moment, and they are also the toughest of the space marine dedicated transport options, so each squad would get one. That also gives me lots of flexibility in terms of deployment, choosing which units I want to bring on early and, within reason, they can adapt to my enemy's deployment to counter them. I started with a couple of cheap 5-man units, one bringing a heavy bolter and the other a flamer. The heavy bolter is simply there for some cheap firepower (and benefits from the Imperial Fists chapter tactics of course), whilst the flamer is there to clear out horde-style models if I need to. The third squad I went a bit more to town on, sticking with the drop pod, but boosting it up to 10 men and giving it a grav cannon and grav gun. This squad could therefore reasonably look to put out quite a nasty amount of firepower against more heavily armoured units (obliterators for example) that my other tactical units might struggle to hurt. They would also benefit from the Tactical Doctrine, that I can enact twice in the game thanks to the demi-company rules.Next choice was a devastator or centurion devastator squad. Now I know centurions are amazing, and the firepower they put out is terrifying, but I've been hatching a plan for a while on this one. At a similar cost, a devastator squad puts out significantly more damage potential than centurions, assuming all other things are equal, with an additional 5 shots. Granted, they aren't anywhere near as survivable, but in output terms they're scary good. The problem is they aren't relentless, but that can be solved with the judicious application of a Cataphractii Terminator Captain, like the one I recently bought from eBay, who not only comes with the slow and purposeful rule, which grants his unit relentless, but also gives the unit a great wound tank with a 2+ save, 4++ invulnerable with the option to re-roll '1's thanks to its overlapping energy fields. Ok, I went filthier. Give that same captain the shield eternal and he is now immune to instant death despite his T4, and his invulnerable save improves to 3++, still granting re-rolls of '1's. Give the sergeant a combi-grav and this unit now puts out a truly frightening 23 grav shots at 18" range, 20 of which will re-roll to wound and all of which are twin linked for a turn and can re-roll '1's to hit for two more turns. Once again these guys would go in a drop pod, the beauty of which is that my opponent may very well deploy to account for them to drop in on turn one, whilst I could then call their bluff by keeping them back if necessary.Next up I needed a fast attack choice. The demi-company actually gives you quite a bit of choice in that regard, with the assault squad, bikes, of varying kinds or land speeders. The assault squad is the choice that most obviously benefits from the doctrine system, but even then their damage output is lacklustre. One thing the army is seriously lacking in at this point however is mobility - I can put the drop pods pretty much where I want them, but after that there's not much they can do to get around the table. Bikes were, and are, a good choice, but having just finished painting up my hunting force I'd had enough of them, and looking through the codex entries once more I noticed that a squad of three Landspeeders gets an extra 6" on their flat out distance. Interesting, and they'd also be objective secured thanks to the demi-company rules. Heavy bolters on top would get re-rolls from the chapter tactics, and I'm a sucker for assault cannons, especially ones that can extend their range by 12" before they fire! Three tornado speeders therefore would spit out 21 shots at S5 and above, with over half of those being S6 and rending. Nice. Equally, speeders having deep strike would mean that I didn't have to show my hand straight away, I could always keep them in reserve if I needed, and they would be fast enough to achieve most anything I needed them to.So that was the core choice complete, now I needed to flesh out the supporting elements.One of the key parts of those supporting elements therefore was to figure out how to get Kantor into combat. Ordinarily I'd be looking at something like a land raider or storm raven as an assault vehicle, but they're hellishly expensive for what they bring, and the new psychic powers bring a considerably safer way into combat than can otherwise be achieved, in the form of the electrodisplacement power. The best way to get that power? Well, a conclave of course, so in came three level 2 librarians. I'd look to pick up the electrodisplacement power for these guys first, and then my second port of call would be my old favourite biomancy, in the hopes of getting endurance to give a unit 4+ feel no pain. The third of the librarians would be a useful addition however to the devastator squad I felt, so I gave them terminator armour and a storm shield to give a bit more protection to my grav cannons. If everything went according to plan therefore, I could always go for something like perfect timing to grant the grav cannons ignores cover (Saturday's tournament gave me first hand experience of just how much this combo can hurt you).I've still not got an auxiliary choice in my Gladius however, and don't have many more points of my original budget of 2000 left to play with. Thankfully however there's a formation in there that plays perfectly into the strategy I've outlined above. Using the electrodisplacement power to slingshot Kantor's unit into combat relied on something very specific, and that's having a unit in a position at the end of it's movement phase that once switched would allow a comparatively straightforward charge. The 10th company taskforce brings a couple of things to the table in that regard. First and most importantly it brings 3 units that can infiltrate and then scout up close - scout bikes in particular are very nasty in this regard. Effectively they can position themselves 24" away from their deployment location to allow the displacement power to work in the first turn. Secondly, they're pretty cheap and the scout bikes can booby trap a piece of terrain, perhaps forcing your opponent to think twice about moving through it.A couple of minimal sniper squads and a bike squad therefore got me nicely up to the 2000pt barrier.So how does that leverage the detachment overall?Well, I mentioned right back at the start that objective secured was a big part of it? Well this list brings 11 obsec units, nothing to be sniffed at and almost two units for each objective in a maelstrom mission. Added to that, we then have Kantor and the Honour guard, great for taking down most units short of the most optimised combat units, and easily capable of tying down or hurting most units in the game. They would also make the most of the use of the Assault Doctrine, their high number of attacks getting great value from the ability to re-roll '1's. The Devastator Doctrine equally would give my Grav Devastators maximum value from their high rate of fire weapons, and the tactical doctrine benefits everyone for another two turns.Short of focusing all my effort on picking up a pair of demi-companies and not having much else on the table, this list is right up there as about the best I can think of, with its only real weakness being flyers. That being said, I'm not expecting that we'll see all that many flyers in the future, and even if I do come up against one or two, the fire volume from some of my units should have me covered.Ok so I mentioned I had two examples, but this massive wall of text is probably enough for now I think, so I'll come back and revisit the Sternhammer list in a few days.