The Emperor’s Sword: Heavy Infantry

“Heavies! What is your profession?”

“Bein’ the chewy meat center in a vanadium-plated god of war, SIR!!”

– apocryphal

Making up three of every sixteen legions (i.e., one for every three light infantry legions) – again, not counting the various specialized legions built off a heavy infantry platform – are the heavy infantry legions. They’re the tip of the spear, the claw on the paw, the hard-strikin’ leading edge of the attack – if the light infantry are the backbone of the Imperial Legions, one might say that the heavy infantry is the bloody great horn on the end that the animal’s charge rams into its enemy with great force and vigor. But the important thing to understand about the heavy legionaries is the nature of their combat environment, and how it makes them infantry – at least partially – by courtesy alone. They’re not just big, tough legionaries in armor; the light infantry have that covered.

So let’s talk about the M70 Havoc combat exoskeleton, the current standard wear of the Heavy Legions. (Which is a combat exoskeleton because it’s descended from a long line of ancestors including, up front, civilian models used for construction, rescue, and so forth. It’s also fully-sealed powered armor, but then, so’s the N45 Garrex.)

Well, it’s big. It looks like a giant, stocky, barrel-bodied, dome-headed, no-necked humanoid with a back-sized hump, with weapons to match strapped to it. (And sort of as if it might overbalance backwards; it won’t, the gearing is much better than that and the armor is heavier in front to counterbalance, but the size of the powerplant and the auxiliary systems it’s carrying back there do create that impression, somewhat.) What it is, is basically a walking tank with interchangeable modular heavy-weapon packs that let it blast away on the battlefield, punch out small buildings, throw respectably-sized vehicles, dance a merry jig amid venting plasma, and toss around nuclear grenades at close range.


If you take your nominal average wearer as being, oh, 7′ x 2′ x 1′, then while light infantry armor makes ’em bigger, it doesn’t make ’em so much bigger that they can no longer fit through doors, and so forth. The Havoc, contrariwise, makes its wearer more like 12′ x 4′ x 4′, and weighing something close to, maybe even on the far side of, a ton. There’s a reason military bases aren’t built to normal scale, and indeed, why you usually use the light infantry if you need to do the kind of building-clearing where it’s important that you’re left with an intact building afterward. Chap in a Havoc runs into your average suburban house hereabouts, he comes out the other side without noticing much of a stop, and it basically implodes. So it goes.


The wearer/operator goes in the front. The whole body opens up at the front, hydraulically, forward and up; the legionary climbs in backwards, then sticks his head up into the helmet and arms into the sleeves; then it closes again. The sleeves are internal to the body, not inside the arms of the suit; you can’t wear a suit that much bigger than you without risking tearing your arms off with every maneuver. Technically, when you’re fighting in a Havoc, you’re doing so with your arms at your sides, slightly bent, resting on the emergency hand controllers and keypads.

Those are only for emergency backup control, though. For primary control – if you’re wearing the suit right, the command torc built into the base of the helmet is resting right up against the back of your neck and the virtuality laser-port they installed in there, if you didn’t have one already, about halfway through basic, and has already established a high-bandwidth data connection with your brain. The moment you go active, you’re no longer wearing the suit and moving it about like a marionette; you are the suit, and moving it like your own body.

(Given its radically different capabilities, of course, this can be tricky to learn. That’s why they spend months teaching you Piston-Driven Fist Style martial arts, designed for these things, before letting you get anywhere near a combat exoskeleton for real; it’s also why an active-service heavy legionary is easy to spot on the street, because his gait will always be that little bit off.)

What they’re wearing in there is a very similar silk organza-type body glove to the one worn under regular combat armor; and exactly like its counterpart, it’s woven through with internal networking and environmental control and medical systems, capable of self-sealing, closing wounds, dispensing emergency pharmaceuticals, and covering everything in NBCN decontamination foam if penetrations are detected. The main difference here is that it can get hot in there; the Havoc bodysuit includes sweat-removal facilities (which filter water removed for the drinking reservoir) and Peltier cooling, run off the main power systems. This, and the legionary wearing it, fit tightly into the suit’s internal gel-filled padded sleeve that cushions them against acceleration and shock.


Naturally, all of this uses a lot of power. A lot of power. This is buffered through distributed superconducting-loop accumulators throughout the exoskeleton, but while they do provide enough power to let you keep moving for a while if you lose the main power plant, they aren’t really enough to actually fight it. For that, you need something that can generate the necessary power.

Ordinarily, they might solve that problem with an antimatter (except that’s not good stuff to keep around where people might be shooting at it) or fusion reactor (except they involve lots of auxiliary machinery to keep the reaction sustained, which also makes it stop working fairly readily when people shoot at it). To bypass those problems, they reached back a little in history, and what’s under the small of this suit’s back is a good old-fashioned micro-fission reactor, of the thorium molten-salt design (which is to say, tasty “hot soup”). This is much more resilient under fire – although if someone does manage to penetrate the armor and crack the flask, it does have the minor disadvantage of spraying highly radioactive heavy-metal fluoride vapor over the landscape. But you can’t have everything.

Sensors and Communications

Core sensors and communications are essentially identical to light-legionary combat armor; radio and whisker laser communications, access to the OTP-encrypted military mesh, threat identification systems, teamware and C3I systems integration, thermal imaging, remote sensor access, 360 degree sensing, etc., etc. It also incorporates the sound transmission and imaging systems, which are even more important in the case of the Havoc, since its “helmet” is a sealed armor-dome with no direct vision possible; all internal displays are produced by the battle computer. The internal computer is rather more powerful than that included in, say, the N45 Garrex, both to run the more complicated systems and to act as a more major node in the battle ‘mesh.

On top of this, the Havoc adds pulsed-usage radar and lidar systems, plus integral T-ray high-frequency snoopers, powered by its greater reactor capacity, and a full ECM suite.

Structure, Strength and Armor

In construction terms, outside the padded sleeve is the diamondoid-composite skeleton of the suit, a honeycomb-patterned framework to provide the basic structural strength of the armor. This includes the attachment points and channels for the “muscles” – pseudo-organic structures capable of changing length on electrical signal – which power the suit. (In conjunction, yes, with the stabilization gyros.) They’re calibrated for high strength, speed, and flexibility; a Havoc is designed to let its wearer run at 54 mph and lift over a ton within safe tolerances – while still being able to dance a jig and pick up an egg without breaking it.

This skeleton is environmentally sealed and environment-controlled, for NBCN protection and exotic atmosphere/vacuum use, able to withstand and operate within several hundred atmospheres of pressure and extreme temperatures. Also at this level, all the working portions of suit equipment (computers, sensors, life support, medical support, power distribution, etc.) are located and secured in place. All of these systems are spread out throughout the skeleton, constructed from highly redundant circuitry with automatic re-routing, so that even with heavy damage, it can still function. It also includes mounting voids for heavier subsystems, such as the power reactor, external hives, and modular weapons pack.

The armor on top of this is qualitatively similar to light infantry armor – a sandwich of interlinked, highly corrosion-resistant and refractory cerametal composite armor plates around electrical and thermal superconductor meshes, with an outer anti-energetic ablative layer sprayed atop it. There’s just a lot more of it, quantitatively speaking, in thick, overlapping slabs. Likewise, the Havoc comes with rather more kinetic barrier emitters than light legionary armor, and thanks to its thorium reactor, has a lot more power available to back them up with. Finally, some portions of the armor include reactive sections, capable of exploding outward to neutralize force from external explosions or impacting projectiles (or, occasionally, long drops), in deference to the fact that large anti-materiel weapons are fired at heavy legionaries with depressing regularity.

There are, generally, no chameleonic or “stealth” features included – and the heavy legionary exoskeleton does not come in any “scout” variants – since the thermal – heat has to be radiated! –  et. al., signature produced by the reactor and other exoskeletal systems are more than enough to vitiate attempts at stealth. On the other hand, it is equipped with the abovementioned ECM and signature-scrambling systems to confuse incoming guided missiles out of perfect target locks.


The Havoc can also fly, at up to several hundred mph depending on local conditions, using a combination of the same vector-control trickery used in standard combat armor, and of using its power reactor to provide the working heat to nuclear-thermal thrusters. (This is normally only an option in atmosphere, which functions as the supply of working fluid; in vacuum, it requires carting a big clip-on tank of remass around with you, which is less than convenient most of the time.) As in the former case, using this for extended flight is discouraged since it makes you an easy kill for air vehicles; on the other hand, it’s great for attaining position, making short skips, and so forth, not to mention extended low ground-skims. Attempting combat parkour with it is possible, but do bear in mind the strength of whatever it is you plan to bounce off of in the process; smashing right through it is often tactically awkward in combat situations.

Integral Weapons & Point Defense

In addition to weapons supplied by the modular pack, the Havoc possesses four integral weapons systems. Two of these are inbuilt to the arms of the suit: on the right, a heavy carbine equivalent to a tribarrel version of the IL-15i Battlesystem‘s carbine section, for routine anti-personnel and light anti-materiel use, and on the left, the KF-15 Dragonspume anti-nanitic/area-denial flamer, serving essentially the same purposes as they do for the light legionary only more so. The EI-12d Valkyrie target designator is built into the helmet section of the Havoc, for use in designating targets for the tactical net and ortillery, etc.

The fourth is a collection of defensive weaponry: each shoulder bears a point-defense pack, consisting of a pair of short-range lasers (designed to cause spontaneous explosion or vaporization-induced deflection) and a pair of short-range autocannon, independently and automatically targeting incoming fire for destruction.

The Havoc also carries an exoskeleton combat knife, which resembles a large hanrian – too heavy for unaugmented sophonts to use – scaled to the exoskeleton, which can be picked up and wielded by its manipulators for use primarily as a utility blade, although melee combat usage isn’t entirely unknown.

Swarms and their Hives

The Havoc also comes with swarm hives, both internal and external, housing microbot/nanobot swarms. The internal hive(s) are integrated into the structural honeycomb, housing repair and medical ‘bots whose purpose is to crawl around the interior of the suit ensuring that it self-repairs, and even more importantly, it keeps its operator in good repair.

The external hives, on the other hand, are a reflection of the Legions’ belief in really close air support. The exact mix can be varied by pre-mission module swap-outs, but a typical default mix for the external hives (the M-823 Horde) is a roughly equal mix of eyeballs, shrikes, gremlins, and balefire – which is to say, of expendable recon assets, counter-swarm swarms, anti-machinery swarms, and anti-personnel/area-denial carbon-devourer swarms.

Modular Weapons Pack

The primary weapons of the heavy legionary, however, are those supplied by the modular weapons pack: again, selected according to mission. The modular weapons pack fits onto the upper rear of the exoskeleton, beneath the armor and behind the helmet, with hardened lines running to extended firing packages which clamp onto the suit’s arms. A typical “mixed-mission” modular weapons pack would be the BP-400 Conflagration, which adds to the integrated loadout the following:

  • An arm-mounted heavy tribarrel sluggun, a larger-bore version of that included in the IL-15i Battlesystem, capable of firing larger (1.5″) versions of all its different ammo types: anti-materiel spikes, flechette canister shot, bore-compatible grenades, or gyroc micromissiles, the latter of which can include as their payload exploding shells, incendiaries and napalm, cryoburn shells, nanoweapons (if someone’s set up a microwave power system for them), chemical/gas dispensers, cyberswarm dispensers, network node – or spy dust – dispensers, injector needles (at low power), restraint nanoglop, electroshock “stunner” shells, acid globs, anti-electronic fiberdust, mollynet, antimatter nuke-in-a-bullets, etc., etc. Naturally, the weapons pack can store plentiful supplies of multiple types, and switch between them on the fly. (One that they’re particularly fond of is the infamous “backscratcher”, which travels a short distance and then blasts flechettes back down at the firer, rattling harmlessly off the heavy armor but making a real mess out of any lighter infantry trying to attack it close up.)
  • A chemical/nanoweapons dispensing system, with storage tanks for same.
  • A backpack vertical-launch system for a half-dozen minimissiles, usually supplied with 0.1 kt microfusion warheads.


Like the light legionary, the heavy legionary is accompanied by and acting as the command nexus for a half-dozen AI combat drones, in this case usually mixed from the WMH-4 Octoscorp, the WMH-7 Grizzly, and the WMH-12 Skyorca, depending on mission parameters, each heavily armed in its own right. When not commanded otherwise, these too default to acting as defense platforms – but the best defense is a good offense, right?


Like the light infantry, the heavy infantry is usually delivered to the field by the G5-TT Corvee tactical transport, fulfilling its multipurpose role. The module used for heavy legionary transport, however, is somewhat different – it’s an open frame, and the legionaries ride on the outside, held in by suit-controlled magnetic clamps, the Havoc already being heavily armored enough. The weight savings permit systems to let them refuel and rearm in flight to be added instead of all that wasteful hull.

They don’t generally use IFVs/APCs to get around on the battlefield. A platform like this doesn’t need ’em.


– rookie heavy-legionary

“Heh. Heheheheh. Here’s a taltis, kid…”

– commander of Basher-class heavy armored vehicle

8 thoughts on “The Emperor’s Sword: Heavy Infantry

  1. Pingback: Trope-a-Day: Le Parkour / Combat Parkour | The Eldraeverse

  2. Pingback: The Emperor’s Sword: Light Cavalry | The Eldraeverse

  3. It is fairly certain mollyblad and mollynet mean “molecular blade” and “monofilament net” respectively. However cyberswarm is somewhat more prickly(evolving scrapcode/computer virus dispenser microbot swarm, I presume?) and I have completely no idea what fiberdust is – fiber composed screen/smoke/tear/choke/disable bomb, perhaps?

    And it seems light and heavy Infantry are utilizing slightly different set of combat drones and nanites – is it correct?


    • The first two, indeed so. (Well, “molecular net”, technically, but what’s in a name?)

      Cyberswarm is just the generic term for self-mobile microbot or nanite swarms.

      Fibernet is an antitechnology weapon: a cloud of tiny carbon-fiber filaments, light enough to be carried by the air everywhere through a given ventilation system, and short out everything it touches in a million different places. And be almost impossible to get rid of.

      And yes, that’s correct: each according to their different battlefield functions.


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  5. I do hope you don’t mind this attempt at constructive criticism 3 years after the fact, but I feel that something needs to be said regarding the size of this contraption.

    “The Havoc, contrariwise, makes its wearer more like 12′ x 4′ x 4′, and weighing something close to, maybe even on the far side of, a ton.”

    With all due respect, I suspect that any real life implementation of a Havoc-like combat mech will either be significantly smaller dimensionally, or significantly larger in terms of mass.

    Consider that record-setting captive Kodiak bears of comparable/inferior height (10-11 ft) can weigh as much as a thousand kilograms. Not only is this Havoc combat mech considerably more robust than such animals, we may presume that it is considerably denser, being made of cerametal and such.

    My suspicion is that anything remotely like the Havoc will weigh in at around five tons. This isn’t to say that agility and grace in such a device would be impossible to achieve, just that actually achieving them will be considerably more impressive than you seem to have expected.

    This isn’t to say that your work is of low-quality. In fact, I find your blog quite enjoyable! This isn’t supposed to be a bashing of your work, just a minor nit-pick that (I hope) you can use to improve the world you are building.


    • No worries – it’s a fair point you make, given what’s revealed here, but just to clarify something:

      Not only is this Havoc combat mech considerably more robust than such animals, we may presume that it is considerably denser, being made of cerametal and such.

      The density, actually, is the thing that throws it off. Basically, mass and weight are two of the biggest issues in building these things, because of (a) inertia, which gets you into an arms race of how much force you can get your actuators to observe versus how much mass they add; and (b), even more critically, ground pressure. A combat exoskeleton doesn’t do you any good at all if it sinks into the mud, and even less if it sinks into the concrete… 🙂

      So while there are notably heavy components (that cerametal armor, for one, and the primary structural members of its “skeleton”), the designers have gone all-in on the fancy materials to save on mass: an astonishing proportion of the internal components are composed of aerogel, metallic foam, and other extreme-low-density substances to keep it within a useful range.


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