Playing with toy soldiers is well known to be one of the most expensive hobbies known to man. Not just because individual models can be spendy, but because you need many for an army- and we generally get it in our heads that we should make a full fledged army. I mean- who wants just one lists worth of models?! I certainly don't. To be honest, I want a full fledged deployable unit's worth of whatever army I'm making. Imperial Guard? I need a short battalion (you know, three companies of infantry supported by a weapons company and maybe an armored company- and mechanized if possible please). Space Marines- well, a chapter would be nice... You get the picture. Assembling a force of one thousand Space Marines can get really expensive- and that's if you don't change you mind, and start all over again. Assembling a fully mechanized Imperial Guard battalion complete with aerial assets and armored support? Cheaper to buy a new car.
That aside- assembling a force isn't only about getting the models and organizing them. That's only one part of the hobby. GW (and Mantic, and Warlord Games, and any other good game company) already have a portion of the work done for you. They have models you can buy, and armies already thought out for you to play. But for me, the real fun comes from creating an army that is wholly unique. Sure, it can be made up of a companies models (like GW's Space Marines, or Mantics GCPS) but the true nature of the army in question is totally up to you. How you field that army- how it plays on the table top and looks when fully assembled- isn't just driven by your aesthetic desires, but by the way the army works.
Let's look at the Space Marine force I want to create- a spec-ops behind enemy lines kind of force. A force like this is going to be infantry centric with limited armored assets. limiting my choices is a great start, and I already did that when I selected the Deathwatch codex as my base rules set. But I still want versatility, as a behind the lines force is going to favor a diversity of tactics with limited resources. The Deathwatch codex allows for this. I can put my specialists into their own units, or I can spread them out into other squads. Think Intercessors squads. They can have Hellblasters, Inceptors, Reivers, or Aggressors attached to them, or I can simply field those units (the attachments) as their own elements. Doing this won't alter my points total, but I can vary my tactics depending on my enemy, and do so on the fly without re-writing a whole list. The points are there- I just have to re-arrange them. But there are some holes in a Deathwatch formation that I want to plug- mainly targeting characters.
There are a few units I can ally in that will allow for this, but only a few that I really want. Assassins have always been a "go-to" selection for me. They provide unique capabilities, and with the re-write of their codex, have become a massive force multiplier. The other is the Primaris Vanguard models. The Eliminators are cheap, and can target characters, and the Infiltrators can push deepstrike out an additional three inches. The Librarians- oh man. Scryers gaze coupled with those Eliminators and that Mindraid- a thing of beauty. All those forces are clandestine behind the lines kind of forces, and fit well with my army idea. I have to ally them in, and some people find soup lists abhorrent, but my goal is a cool themed army with it's own strengths and weaknesses- not to make my opponent happy.
This concept mapped out, now unit selection takes place. The bulk of my army can be whatever I want. Maybe the principle force is the Vanguard with the Deathwatch assets in support priding a distraction for the assassins. Perhaps the opposite is true. Either way, the list created will tend toward a certain play style depending on what I choose. If I'm looking at demolishing the enemies command and control, snipers supporting assassins will be immensely important. If I'm looking toward wrecking the entire army, Intercessors with supporting Hellblasters will probably become my central focus. Any way I swing the army in a game, I want the elements to back one another up, and cover potential holes in the list.
It may not seem obvious, but the force described is limited in units, but maximized in potential game strategies. There are weaknesses I have to deal with (a lack of invulnerable saves in a world of heavy weapons with 2 damage each springs to mind as well as limited anti-armor), but those can be mitigated by exposing my opponents weaknesses faster (a strategy that any guerilla force would seek to enact). I've discovered the Intercessors with SIA are a force capable of ruining most if not all light infantry forces to heaping mounds of bodies And the ability to re-roll wound rolls of ones for an entire gunline against a certain class of models isn't to be ignored- especially when your doing it at 36" with an AP of -2 (and it gets worse the closer you get). Couple the Intercessors impressive firepower with other units ability to single out character models, and you have the potential to break an army very quickly, and deny them the ability to control objectives.
The goal is simple- remove command and control assets, and reduce enemy troop concentrations rapidly. Armor isn't my concern (though it could be when I'm facing an armored formation led by tank commanders- but I'll deal with that when I get to it), eliminating HQ units is- because that's what a Guerilla force would concentrate on. And on the table top, reducing troops selections quickly, as well as the buffs that characters give them, will grant me the ability to win on points if need be (so long as I can keep my characters and troops alive long enough to capitalize on the ensuing confusion). The force in question has all the things I want- flexibility, focus, and a cool vibe. Next, I'll have to assemble it to match the play style.
I hope this illustrates how to build a force around an idea. I'm looking to get into this kind of stuff more. The game play is still a learning process for me, so I'll concentrate more heavily on what I love about the hobby most- making cool looking models and themed armies. As such, I'm going to start a series called "Conversion Corner" wherein I will do simple conversions so you- the watcher- will be able to see how I do it, and get an idea of how to enter into the wonderful world of converting miniatures. It's an art form, and immensely satisfying. I'm going to start by making myself a Primaris Vanguard force from non-Vanguard models for the list I described above. Should be a lot of fun. After that- who knows.