Subterranean Assault

The main focus of a subterranean assault list revolves around the use and application of the following two units.

### Terrax-Pattern Termite Assault Drill

This unit was a (fairly) recent addition to the Horus Heresy, and a welcome one at that. With a 12 man capacity and sporting a pair of combi-bolters that can be upgraded to heavy flamers or volkite chargers, the termite is a reasonably cheap transport considering what it can do, clocking in well below 100pts (even when upgraded somewhat) and having far higher armour than a typical Rhino transport has.

### Ordinatus Aktaeus

This is the second subterranean assault unit added to the Horus Heresy, and is the first super heavy subterranean transport. Available only for the Mechanicum (for now). Costing well over 700pts, but equipped with a decent ranged support weapon (in the form of a 12 shot autocannon at AP5 essentially) and a whopping 14HP with AV14 on the front and side facings, this monster won't be disappearing in a hurry when it arrives.

## Overview

### General principles

The purpose of a subterranean assault list is simple; deliver devastating firepower from underground, and avoid using units that either cannot deploy from them, or wouldn't be thematically appropriate fielding alongside them. Depending on how strictly you are playing this type of force, you will be limited on the following.

* Flyers, as bringing them would not make sense for a subterranean assault force
* Drop pods, as you are striking from beneath, not above

It depends how strictly you want to adhere to the "limitations" of such a force, but it can be quite rewarding to field a subterranean assault force without needing to use units that wouldn't appear in such a force in the lore.

### Limitations

The biggest limitation on the subterranean assault force is how many termites you can bring, as they consume a Fast Attack slot each, meaning in most lists you are limited to 3 of them.

### Dedicated transport

The obvious choice for this is anything that can take a termite as a dedicated transport, so that essentially promotes the following units.

* Legion Destroyer Squads
* Imperialis Militia Grenadier Squads
* Velataris Storm Sections/Auxilia Flamer Sections
* Scyllax Covenants

These units can all take a termite as a dedicated transport, which will allow you to take them in greater numbers.

## Preparation

### How to equip your termites

This is a tricky one, because a termite is a standard vehicle, if it moves it can only fire one weapon at full Ballistic Skill, which means upgrading to heavy flamers may seem like a good idea on paper but you'll only be firing one a turn on average. A good recommendation is just to stick with the standard combi-bolters, as they can be very handy in a pinch and can still bring down a terminator that's unlucky enough to fail its save.

### Who should be in termites

You want to put units that have an emphasis on short-range engagement, or melee in termites. Sadly, they aren't assault vehicles so you will need to make sure if you have a dedicated melee unit in a termite that they can be protected long enough to charge the following turn. This mindset lends termites to be very effective when containing the following units.

* Breacher Squads
* Combi-weapon units (such as Veteran Squads)
* Units equipped with short-range weaponry (such as phosphex bombs and plasma pistols)

These units are good to take in them, and the fact they make Breacher Squads more useful is wonderful. Chuck in a couple of Breacher Squads with melta bombs and a few meltaguns here and there and you have a really hardy unit that can weather a lot of incoming fire and still present a good threat to your opponent.

Because termites have a 12 man capacity, it means you can run a basic 10 man unit in them, plus an Apothecary and even an HQ choice; this is brilliant, as it means you can have a close combat Praetor hidden inside a unit such as Breachers or Veterans to provide some scary melee capability and further deter opportunistic charges against that unit.

### Using the Ordinatus Aktaeus

So this may just seem like a big termite, but it's far more than that. Capable of transporting 40 models (including jump and jet pack infantry) as well as having up to 3 automata in that complement (each counting as 8 models), it can deliver a lot of firepower to your opponents face. The main restriction it doesn't have unlike the termite is that it can transport bulky and very bulky units. This means that you want to deliver units in an Aktaeus that can't normally get in a termite. A solid loadout for the Aktaeus would consist of a sledgehammer unit of automata, some fire support units and a few characters to make the most out of your offensive push and keep your robots in line. A suggested loadout follows.

* 3x Castellax (or Domitar) automata
* 2 units of 3x Thallax or Myrmidons
* Magos Dominus (to babysit the Castellax)

This still leaves you with a few empty seats onboard, so you can throw in another HQ choice in there, or upgrade your Dominus to have things like an abeytant or other tasty upgrades that make him a little larger than before.

## Application

### How they work

When a Termite or Aktaeus deep strikes, they essentially follow these steps.

1. Place a large blast (or apocalyptic mega blast for the Aktaeus) so that it is over 1" away from all units, friend or foe.
2. Roll your scatter as normal and move the template.
3. The Termite or Aktaeus can then be placed in any orientation, provided at least part of its body is fully over the centre hole of the template.
4. If you scatter onto an obstacle (such as a vehicle, building, unit in melee or impassable terrain), reduce the scatter distance to avoid the obstacle. The unit in question then suffers some damage as a result.
5. If you would be placed on any other unit, the other unit moves out of the way to allow you to place your vehicle in the desired position. Anyone who cannot move out the way via the shortest distance and remain in coherency is remove from play.
6. The unit can then disembark from the vehicle if they wish as normal.

***Please Note:** When the Aktaeus arrives it becomes irreparably immobilized, so make sure it's positioned right as that's the only chance you'll have to move it.*

It's as simple as that, but it's important to remember the steps involved as they may seem like oversized drop pods initially, but they do have a few major differences that are worth remembering to avoid embarrassing deep strike moments.

### Mobile cover

The big question I hear people ask all the time in the eternal debate of drop pods or termites is "why would you take termites over them, they're more expensive and do pretty much the same thing". There is one key difference (beyond the increased capacity) that provides a huge boost in favour of the termite. The termite can completely block line of sight, the drop pod cannot. Use this to your advantage and screen your more vulnerable units with the bulk of the termite. There are two main things that blocking line of sight like this protects you from.

* Units with interceptor and scary weapons that could threaten the unit that just disembarked
* An aggressive melee unit that you don't want charging you immediately.

This gives you much more control over where your units arrive, as you can protect them from a lot of the threats a deep-strike heavy list usually is afraid of.

### Movement denial

Termites are quite big units, and the Aktaeus is enormous at over 14" long. These units can be used to essentially herd an enemy force in the direction you want them to go. While they can assault the drills, or destroy them with ranged firepower, it will still force them to divert assets and effort to destroying these things rather than the units they have delivered. A carefully placed Aktaeus or pair of Termites can block off an enemy flank completely, or even cut their army in half if you get lucky with your positioning and scatter.

### Vehicle sniping

This is a tricky one to pull off, but if you place your arrival template nearby a dangerous vehicle (like a Whirlwind Scorpius or Arcus) then you can hope for a scatter onto it. This can either outright destroy it in the case of the Aktaeus, or force it to snap fire in the case of the Termite. Either way, it can neutralise that vehicle as a threat, and give you less things to worry about in your next few turns. This is entirely chance based though, as you have to be 1" away from the vehicle when you declare you're arrival, and then hope your template scatters to clip the vehicle. Use at your own risk, but it's worth trying if you need to make a grand entrance.

### Deep striking nuclear bomb

This applies to the Aktaeus, as it is a super heavy vehicle, and therefore explodes in a somewhat ludicrous way. If you deep strike one of these monsters into your opponents army, you present them with an interesting choice; do they ignore the vehicle causing them all sorts of problems, or do they destroy it and risk the explosion scattering onto their units. It's a tough choice, and definitely gives your opponent more to think about when dealing with your arrival.

## Conclusion

In general, the subterranean assault approach is a solid tactic to use in games, as it can allow you to deliver some devastating alpha strike potential whilst also playing to a very interesting theme, and allows you to recreate the assault in Saturnine. Strike hard and strike from below, and bring death to the enemies of the Emperor (or Warmaster).

**Subterranean Assault**