The Acastus Class Knight Chassis is the largest, most powerful and well defended chassis of all Knights. It’s firepower can rival that of Warhound Class Titans. The Acastus Class are broken down into two main variants; Asterius and Porphyrion. This can be further defined as;

Long range fire support – Acastus Knight Asterius.

Anti-Tank/Knight – Acastus Knight Porphyrion.

Their weapons far eclipse the potential of some that are carried by role-dedicated Astartes platforms, and can lay waste to large swathes of enemy Companies when they unleash their firepower.

In Horus Heresy 1.0, the Porphyrion was a tad good; generally being able to stand up to Warhound Titans and cause serious strife for anything lesser. However, things have changed in Horus Heresy 2.0 and in general, Lords of War are overcosted for what they can do or what they can survive. Let’s have a look at the Porphyrion in 2.0 and see where it stands these days.


In Horus Heresy 1.0, the Porphyrion originally cost 460 points (sans upgrades) to field. This was rightfully identified as woefully cheap, and it went to 560 points (sans upgrades) in FAQ 1.1. This was still somewhat cheap, and it should probably have sat around the 580 points mark, with upgrades nudging it over the 600 point mark. Most of it’s greatness was down to the fact it was BS5, so it quite literally sniped and bludgeoned it’s way across the table. It’s important to understand where it’s come from in the gaming system, to truly understand how good it is in the current one.

The Porphyrion can be taken as a Lord of War choice in Legiones Astartes and Mechanicum armies as a stand-alone. I’m unsighted on whether it’s available as such in Liber Imperium at the time of writing. Alternatively, it can be taken in it’s own main Detachment of Questoris Knights or as an Allied Detachment of Questoris Knights.

The Acastus Porphyrion in v2.0 has a basic stat line of:

1244 (5)10141312339 (8)

The Italic bracketed figures are the stats for it in v1.0, which you can see is a mixed-crate of nerf/buff, with most of it remaining the same. The Porphyrion didn’t really need a buff, but the extra hull-point is appreciated. The nerf of the ballistic skill really isn’t appreciated however – this is now a 625 point model, sans upgrades. This is quite the amount of points, taking it dangerously close to the Warhound Titan, which sits at 750 points and has BS5 and 12 hull points. Realistically, if you’re buying into the anti-armour and anti-air capability the Porphyrion can provide, you’re less than 100 points off the Warhound price, and a whole lot less effective than one.

It’s not even that the Porphyrion is more easily purchasable to the masses either – now costing a horrific £412 – which is more than the Warhound Titans body. Sure, you get all the weapons for the Porphyrion, but even with an arm-weapon-equipped Warhound, you’re talking £500-ish, so you’re less than £100 away from a Warhound. At this point, i’m starting to think that Games Workshop are aligning points to the price of models.

You’ll note the addition of the fixed movement value of 12, something that is a defining feature of Horus Heresy 2.0. I’ll come to movement later in this section however, as 12″ movement interacts nicely with some of the other basic rules the Porphyrion has.

As with most of the Super-heavy platforms in 2.0, it’s fairly expensive and fairly medicore when looking at it’s stat line in comparison to, say a Contemptor Dreadnought. Sure, that is a well known unit that is too good for it’s cost, but Games Workshop don’t seem too bothered about fixing/nerfing Dreadnoughts. For the price of one Porphyrion, you can buy three Contemptor Dreadnoughts, or two in Dreadnought Drop Pods. This is a problem because if you pod two Contemptor Dreadnoughts in close to a Porphyrion, it probably won’t be there once they’ve charged it.

As a Vehicle (Knight), the Porphyrion uses the Knights and Titans rules on page 216 in the Age of Darkness Rulebook. One of the core changes to Knights is that they cannot make a reaction to any model unless it has eight or more wounds, or is another Knight, Titan, or Super-Heavy Vehicle. There will be those of you who are versed in Heresy enough to spot the obvious link between the paragraph above (reference cost) and this limiting factor on reactions. Contemptor Dreadnought are six wounds. You can’t Withdraw or even Return Fire, which means if your Porphyrion gets podded by the aforementioned Dreadnoughts, it’s game over for it – especially as Overwatch cannot be carried out by it’s main armament due to the fact it’s a Blast weapon, despite the fact that Knight and Titan arm weapons count as Defensive Weapons.

Knights and Titans may move just like Infantry, with the exception that they cannot Run. This isn’t a huge issue for the Porphyrion, as you’re not likely to want it to run – it’s a gun platform after all. More importantly for the Porphyrion, it ignores all terrain effects and doesn’t take Dangerous Terrain Tests. The only caveat to this is that it may not pass through or end its move in Impassable Terrain. They can also move over units composed entirely of Infantry or Cavalry – but not end within 1″ of any model. This gives the Porphyrion quite solid mobility on the battlefield, especially when coupled with it’s movement characteristic. There aren’t many instances where you’ll find your Porphyrion boxed in and unable to manoeuvre, those that do occur usually will come from castling up too much in your deployment, or the aforementioned Dreadnought issues.

Knights and Titans can’t be destroyed in a single hit due to their size and structure. Instead, when a Porphyrion suffers an Explodes! result, it loses one hull point for the Penetrating hit and a further D3 hull points. It also ignores the effects of Crew Shaken, Crew Stunned, Immobilised or Weapon Destroyed, meaning that for the most part, it’s operating at maximum effect until it is utterly destroyed. This goes some way towards understanding the points cost of the model, but not all the way. Note that it also ignores the effect of weapons which permanently lower the armour value of the model, but rules such as Lance, which count the value as lower are unaffected.

When the Porphyrion is destroyed, it’ll go up good and nuke a fair part of the table. Once it’s lost the final hull point, it suffers Catastrophic Damage and Explodes! When this occurs, you don’t carry out the usual procedure for Explodes!, instead you remove the model and resolve a Strength 7+D3 (for a maximum of Strength 10) with an AP of 4 against every model, friendly or enemy, within 6+D6 (for a maximum of 12″) from the hull of the model (measured before it was removed). Any model or unit that is hit by this also is subject to a Pinning test. There’s clearly a balance between protecting the Porphyrion and letting your army be melted by (un)friendly overloading reactors. I generally look to establish a barrier around the 10″ mark, making it difficult to get Drop Pods or even Deep Striking units in exceedingly difficult.

Knights and Titans in the Assault phase are treated like Infantry models, meaning they can charge (although it is regardless of weapons used in the shooting phase) eligible targets. However, they can’t be locked in combat, meaning that 12″ movement can come in clutch if you get caught out. To counter this, sacrificing models in melee for wrapping the Porphyrion against Impassable Terrain etc can be a good tactic, especially if those models have Skirmish.

If a Knight or Titan is armed with two or more melee weapons, then it gains +1 attack. This isn’t the case for the Porphyrion, which has no melee weapons to speak of, only it’s pure bulk. Knights and Titans have the chance to perform Stomp attacks – and this is what the Porphyrion relies upon realistically. Stomp attacks are resolved at initiative step 1 and the Porphyrion will make D6+3 (it’s unmodified attacks stat, for a maximum of 9 attacks) at WS4, Strength 10 and AP 2. This is pretty effective at deleting Power Armour infantry units, and hurting Terminator units, but realistically, if you survive the first round of combat, you want to get out, and shoot the enemy instead. Stomp attacks can’t be made against other Knights and Titans, Flyers, Super-heavy vehicle or a model with 8 or more wounds. The main problem with Stomp attacks, is that they’re not Brutal – which you’d think would be the case considering you’re being stamped on by a huge, towering behemoth. FAQ needed here I feel. Knights can’t make Consolidation moves, Sweeping advances or Pile in moves.

The Porphyrion has an Ion Shield, and the largest departure from Horus Heresy v1.0 is that it no longer needs to be rotated. Instead the Porphyrion has a 4++ save on it’s front facing and a 5++ on it’s side facing. Note, that nothing is said for it’s rear – making that armour value of 12 simply horrific weak spot that undeniably reinforces how overcosted and weak Knights are in this edition. To put it into perspective, it’d take a single ten-man Tactical Support Squad (Meltagun, 295pts) or Heavy Support Squad (Lascannons, 285pts) to get in behind it, either by Infiltrate or deployment such as Ambush to be highly likely to destroy it in a single shooting phase. Meanwhile, you’ve lost close to a quarter of your army. An extreme case, but one that can easily occur with a canny opponent or bad luck. The Porphyrion does at least have It will not die (6+), though it probably won’t save it.

So, it’s significantly weaker than it was in v1.0 and it has a slightly worse BS for its weapons systems. So, those weapons must be pretty good, right?


The core function of the Porphyrion is to bring firepower to bear and rain devastation down on their targets. So, lets look at those weapons.

The Porphyrion is outfitted with two Hull (front) mounted twin-linked Magna Lascannon that dominate its frame.

Magna Lascannon72″102Ordnance 2, Large Blast 5″

Being Twin-Linked, those 5″ templates can have their scatter re-rolled, and whilst the Porphyrion’s BS is slightly worse now, that still means you’re likely to hit what you’re shooting at, though all three dice must be re-rolled. Ordnance gives it more of a chance to penetrate by allowing you to roll 2D6 for armour penetration and selecting the highest result. AP 2 adds +1 to the Vehicle Damage chart too, making those Explodes! results all the more likely. The best bit is that it’s Ordnance 2, per Magna Lascannon, meaning it’s a total of 4 shots. It’s still a brutal weapon system, even with the nerf on the BS.

So the Primary armament is able to gut enemy targets, but what about the Secondaries?


The Porphyrion has some lovely options to allow it to fill specific roles on the battlefield, though here too there are nerfs.

Ironstorm Missile Pod (Free)72″54Ordnance 1, Large Blast 5″
Whirlwind Launcher with Hyperios Warheads only (+10pts)48″83Heavy 4, Skyfire, Twin-Linked
Autocannon48″74Heavy 2, Rending (6+)
Lascannon (+10pts per weapon)48″92Heavy 1, Sunder
Irad-Cleanser (Free)Template25Assault 1, Fleshbane, Rad-Phage

The Autocannons are free as they’re equipped as standard, and they aren’t a bad choice if you want to keep things cheap but each Lascannon will set you back 10pts for that anti-armour firepower. Finally, the Irad Cleanser is a free swap, adding some further anti-infantry with Fleshbane and Rad-phage helping to clear squads from the Porphyrions path. Personally, I look to run with Lascannons, amping up the threat to anti-armour as much as possible. That said, there’s an argument to using the Irad Cleanser as a point defence weapon to defend the Porphyrion against enemy infantry.

For those wanting some anti-air firepower the Whirlwind Launcher with Hyperios Warheads only is an ok choice. Generally speaking the community isn’t seeing a huge amount of flyers on the table – and there are other platforms that are better suited to anti-air work, such as a Lascannon Contemptor Dreadnought with Helical Targeting Array. It’s simply a matter of choice. The Ironstorm Missile Pod has had a nerf, losing range (down from 72″), Strength (down from 6) and being Large Blast (down from Massive Blast). I’m not entirely sure why this was needed as frankly, it wasn’t overpowered in the first place.


The Acastus Porphyrion is a lovely model, both to build and paint, but frankly the cost of the model is well past being ridiculous. I believe when I bought mine it was £330 – a few years ago. In the current economic situation it’s an absolute joke that a model that costs significantly less to produce has such a high profit margin slapped onto it.

From a gaming standpoint the Porphyrion has definitely received a nerf. It’s expensive in points, and it’s had a few nerfs to the way it puts out its firepower and the firepower itself but the main issue in my opinoin is the Ion Shields rule.

I’m really not sure why they didn’t state 4++ on the front, 5++ on the sides and 6++ on the rear, but having no save on the rear at all enables an enemy to effectively remove a quarter of your army with significantly cheaper forces – to no real cost; as you can’t react to those units in general either due to the rules for Knights and Titans. It’s not even a case of “if your rear is open or you allow a charge from a Contemptor Dreadnought you deserve to lose it” – which I’ve heard uttered in this community recently. It’s just poor rules writing for an expensive large component of your army.

Of course there is another way to run the Porphyrion, namely an Allied Questoris Knight Detachment. You’ll need a further 450-465 points (two Armiger Warglaive and either Arbalester for +1BS at 55 points or Implacable for +1HP at 65 points on the Porphyrion) for it. For some, it’s not really a choice as it takes too many points out of their pool for their builds.

In v1.0 I said the Porphyrion was a “full-table threat” unit. In v2.0 I don’t think that’s the case anymore. The vulnerabilities of the platform aren’t necessarily bought out by its firepower and there are much better and cheaper ways of having full-table threat, though it definitely doesn’t look as good.

As before, the real issue, in both monetary and gaming terms is the Warhound Titan as a centrepiece model. It’s so incredibly close in points and money that if I wanted to amp up my firepower with a genuinely resilient platform, I’d probably just elect for that instead. In v1.0, that decision was far less obvious, in v2.0 it’s clear as day.

Long live the king, the Porphyrion may actually, be dead in v2.0.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.