Goonhammer Reviews: Horus Heresy Third Edition Liber Mechanicum

The new edition of the Horus Heresy is here, and there’s no better time to dive into playing the terrible battles of this dark age. With a full rules revamp, a new starter set and a plethora of army books all dropping at launch, we’re diving in to give you our first impressions of the new edition, hitting the highlights of what’s new, what’s interesting and what’s worth playing in third edition Heresy.

Before we get started, thanks to Games Workshop for sending these over for review.

The third edition of the Liber Mechanicum is a fun one. It’s flavorful, a little convoluted, and certainly different when compared to prior versions of the game and the other Libers launching for preorder this weekend. You will want to read the book fully before putting a list together and after several full read throughs things do come together nicely. But upon initial review you will be assaulted by flavorful if not intimidating terminology and feel an immediate need to create your own cheat sheet as you go through it. Is it perfect? No. But I think the faction is looking super fun and the closest parallel to the narrative of the Horus Heresy era Mechanicum that we have seen yet. 

For the Omnissiah!

The Liber Mechancium gives a player the tools to create a structured army that is made up of several different Tech Arcanas and their specialties of war. Simply put, unlike the Astartes armies that you’ll regularly come onto the table built around a single subfaction (Legion), a Mechancium army is the combination of several. Tech Arcanas are the “subfactions” in the LIber Mechanicum and the entire faction designed to have them play together. 

A Mechanicum army has a lower model count (unless you spam Tech Thralls, which is not a bad idea) than their peers in the Legiones Astartes and certainly less than found in the Solar Auxilia. They are tough and pack a punch, but lack the mass tank killing ability that you might have expected. 

You want to bring an Arch Magos to lead your force – belonging to one of the seven arcanas that those familiar with the faction will recognize. You’ll also want to bring several other Magos, Tech Priests, and Arcuitor Magisterium from different arcanas to unlock the widest range of benefits for your force. You can take any unit but having a HQ or Tech Priest along with them can really add a lot. There is a lot of initial planning that goes into making a Mechanicum army and players will spend a lot of time crunching numbers and correctly selecting the units to layer different benefits across the force. 

Army List, Faction Benefits, and What’s New?

Every unit of a Mechanicum will either be assigned a specific Tech Arcana or will have “[Mechanicum]” listed in its entry. You can only fill a detachment with units that belong to the same Tech Arcana (Logistical Benefit Prime Advantages ignore this stipulation). When “[Mechanicum]” is listed instead of an explicit Tech Arcana, it means you can choose which Arcana the unit belongs to. Keep in mind that when a unit has a mix of Tech Arcana (factions) there is a negative modifier to several stats. 

Now you may ask, what happens when I choose my Arch Magos to belong to Cybernetica instead of Lacrymaerta? Or vice versa? Well a fair amount and this is again a core concept to Mechanicum army building. When an Arch Magos, Magos, or Tech Priest belongs to a certain Tech Arcana, they gain access to several unique benefits made up of an Arcana Benefice, Arcana Options, and a unique Apex Detachment. 

An important side note, similar to second edition, any unit that is also an Automata unit type has a few pros and cons: they cannot hold objectives, make reactions, gain Tactical Statuses, or get routed (the non-automata that join a unit though, certainly can). 

The Liber Mechanicum also provides two Mechanicum specific Detachments, a Thagmata Cohort made up of four support slots (our “Troop” choices from second edition), and an Apprentice Cadre to bring four Troop slots. Note that Tech Priests are the only Troop in the army list. This means that your Primary Detachment will only be made up of your Command slots and whatever Tech Priests you include. 

Now back to Tech Arcanas. At high level, the Tech Arcanas fall into these groups: 

• Archimandrite – The ruling class of the Mechanicum allowing different factions to better work together and improve Cyberthurgy.
  • Arcana Benefice: A buff to your models stats and the ability to join units belonging to other Tech Archana.   
  • Arcana Options: The ability to use two Cyberthrugic Rites in a turn (more on this later).
  • Unique Apex Detachment: An apex detachment of veteran Tech Priests and Retinues.
• Cybernetica – Your robots. Castellax, Thanatar, Domitar, Vorax, Vultarax.
  • Arcana Benefice: The ability to allow an attached Automata unit to Hold, Control, and Contest objectives. 
  • Arcana Options: Any Cybernetica unit with a Prime Advantage can have a model become a Paragon of Metal (a large bonus to several stats, the Sergeant sub-type, and the ability to confer the Cybernetica Arcana Benefice to their unit).
  • Unique Apex Detachment: A combination of a Prime Elite, Support, and War Engine slots (which you naturally apply Paragon of Metal to).
• Lacrymaerta – The combination of flesh and metal. Tech Thralls and Ursurax
  • Arcana Benefice: Your Magos and Priests can heal all types of models whether its infantry, Automata, or vehicles. They are especially good at healing Tech Thralls. 
  • Arcana Options: You can heavily buff the stats of Tech Thralls and Ursurax as a Prime benefit. 
  • Unique Apex Detachment: Three Prime Heavy Assault slots used for Ursurax. 
• Myrmidax – The lords of war and war crimes. Myrmidons of the slashing and shooting inclination. 
  • Arcana Benefice: You turn a Magos or Priest into a quasi Myrmidons who can fight in Challenges. 
  • Arcana Options: A unique gambit for your buffed Magos or Priest in previously mentioned Challenge.
  • Unique Apex Detachment: Lose all your friends by taking 4 units of Myrmidons! One gaining a Prime Advantage. 
• Malagra – The Mechanicum Secret Police. Arcuitor Magisterium.
  • Arcana Benefice: Any enemy Mechanicum model suffers fear -1 from your Magos or Priest. 
  • Arcana Options: A unique gambit allowing your model to buff a stat while in a Challenge based on their Battlesmith (X) value. 
  • Unique Apex Detachment: Create a unit of three Arcuitor Magisterum! They do not provide additional detachments despite having the Command ability. 
• Macrotek – The builders of the Mechanicum and the keepers of tanks. Karacanos and the Krios.
  • Arcana Benefice: When your Magos or Priest is near a vehicle, the vehicle gains a 6+ invuln. 
  • Arcana Options: A prime advantage that grants +1 to a vehicles Front and Side armor (up to 14) and +2 Hull points. Transport Capacity also increases by 2. 
  • Unique Apex Detachment: An extremely efficient set of Three Prime Armor Slots and Three Prime Heavy Transport slots. Giving them the above Prime Advantage is required (but youd want to do it anyways) but this is huge and I expect this Detachment to be a staple of any Mechanicum army. 
• Reductor – The destroyers of the Mechanicum. Thallax.
  • Arcana Benefice: Any unit that has a model with this Arcana Benefice gets a Strength bonus to stationary Vehicles, Buildings, and Fortifications. It also prevents the Shieldwall Advanced Reaction when firing at an Infantry unit. 
  • Arcana Options: A Prime Advantage for Thallaxi – buffing their Prime (Sergeant).
  • Unique Apex Detachment: Three slots of buffed Thallaxi with the above Prime advantage. The bane of breachers and Imperial Fist players. 

Several units as stated have “[Mechanicum]” as a default which is made up of Arch Magos, Magos, Scyllax, Echindax, Tech-Priests, Triaros Armored Conveyors, and Arminger Moirax. 

So with all of this said, what does that really mean for a player to build an army? A player will need to be thoughtful and efficient to bring a 3K army on the table and some units like Vorax, Vultarax, and even Tech Thralls can be a tough fit into a list as you basically have to dedicate a detachment to bringing them on the table. You could bring a one off as a Prime Advantage but again, you will need to be thoughtful and build each list from the ground up based on the points allowed. It is not so simple to just “drop a unit” into your existing list as often the force org limitations will act as a barrier. The Magos (not the Arch Magos) makes things easier by having Officer of the Line (2), echoing their Centurion counterpart in the Astartes list. 

Each Command unit is effectively the “master” of that particular Tech Arcana in your force and I’m really excited to see this modeled across armies. I look forward to subsequent additions to the Mechanicum army list as additional Detachments become available. 

Cyberthurgy

Next up is Cyberthurgy and this is a tough one. Easily the most initially verbose and complex set of rules in the Liber. But basically these allow you to Invoke Cyberthurgic Status’ to units as part of an Intelligence Check. The Status’ fall into one of two categories and get much easier to understand after a full round of reading. 

• Orthodox: The “oldest and widely known teachings of the Mechanicum” that apply benefits to units. 
• Heterodox: More recent “schismatic teachings” seen as improper by some branches of the Mechanicum. They apply negative effects to the enemy and are not explored in this book (Liber Dark Mechanicum perhaps?). 

Any model with the Cybertheurgist Trait has the ability to take advantage of Cyberthurgy or be the target of it. Each turn a player can choose to Invoke one Cyberthurgic trait even if there are several models on the table that could use Cyberthurgy. edit: realSnice – Only one model in a unit may Invoke Cyberthurgy per the controlling player’s turn (I did say this section is confusing). 

This can be done when any unit is selected to move, shoot, or charge but before those actions are actually completed. You cannot Invoke Cyberthurgy if the model is affected by any Tactical Status, in Combat, or embarked in a vehicle. Some Cybertheurgic Rites result in Cybertheurgic Feedback that cause 1 damage wounds (or a glancing hit), only savable by a model’s Armor Save. This comes up often. 

There are three status types that get applied in various ways depending on the Cyberthurgic Rite which is impacted by the model’s Tech Arcana.

• Quicken: Adding =1 to Movement and Initiative. Vehicles get a +3 to move instead given the lack of Initiative. 
• Fortify: +1 to Strength and Toughness or AV up to 14.
• Guide: +1 to Ballistic and Weapon Skill

Cybertheurgic Rites

I won’t do an exhaustive list here and we can get into the strategy around them in a later article but see below for an example and an overview of each. Every Rite typically provides one of the above status’ with various changes to targets, difficulty, and range depending on what Tech Arcana the model belongs to. There are three Standard Rites available to all with Cybertheurigst and Mechanicum Traits. Lacrymaerta and Reductor have 2 while Myrmidax has 1. There is another Rite available to all Mechanicum Subfactions which makes me wonder why it didn’t get included as a “Standard Rite”. 

Standard Rites:

• Programming Interrupt: Provides one of the above status and If that unit reacts in the following turn, it does not cost a Reaction Point but the status is removed. 
• Cogitator Purge: Works similar to Programming Interrupt but targets an enemy unit and removes all Cybertheurgic Status that they may have. 
• Overcharged Reactors: A lower difficulty and shorter range that provides all the Status options of Programming Interrupt but lacks the option to have a reaction be free. 

The two Lacrymaetra traits can target Thralls and Ursurax. One buffs them, applying Status’ and the other removes them from a unit Locked in Combat, forces Feedback on the models, and if any die they score S6 AP5 hits against any other unit in a melee. The two Reductor traits target vehicles, with the first forcing a unit (friend or foe) to disembark from a bundling, vehicle, or fortification (hilarious) or the other buffing vehicles with a Status at longer range (24”). Fury of the Ages is dedicated to Myrmidax and give their units Fortify or Guide while locked in combat. Finally, the previously mentioned Rite that should be a Standard one, Chastise the Machine Spirit targets the non-Automata of the game (whether that’s Astartes, Solar Aux, or other Magos), giving them the Stunned or Suppressed Status through what is described in flavor text as hacking into their opponents wargear (love that). 

What’s Missing (Dark Mechanicum)?

So the elephant in the room here is where are the Dark Mechanicum? Are they present? For that, the answer is no. At least a dedicated faction of Dark Mechancium in contrast to the Mechanicum are not. That being said, the Machine Malefica are. 

While not providing unique Tech Arcanas, by using the Machine Malefica rules you can turn any Cybertheurgist into a Heterodoxist (heretic). They must be Traitor and also get the Malefic trait which prevents all Tactical Status from being applied to a Unit (who instead suffer D3 (dice roll), AP2, D1, wounds with no possibility to save), cannot have a negative modifier to Leadership, Cool, Willpower, or Intelligence, or join any non-Malefic units. 

They get two unique Cybertheurgic Rites and finally you can also take advantage of the Decimator, Blood Slaughterer, Kytan, and much loved Brass Scorpion, adding them to your traitor armies. I can only assume that something more is coming, between a teased spooky Mech Infantry unit, and some other language in this book, a follow up Liber for the Dark Mechanicum is likely on a roadmap or in a slide deck somewhere. In the meantime, the Machine Malefica are a great couple of pages of rules to hold one over until we get all the Tech Heresy back in our hands and in an upgraded form (considering what is provided in this Liber today). 

Other notable omissions from the book include. These might come back in Legacies or further Journal Tactica:

• Calleb Decima Invictus is lost after his death at Istvaan.
• The Arlatax is not found here despite existing in Legiones Imperialis.
• Mechanicum Knights now stand on their own (but are very easily allied, check out our separate article dedicated to the faction). 
• To great sadness I must announce the removal of the Ordinatus Ulator and Aktaeus from the book. This unit has always been a white whale of mine and while I did notice nearly a year ago when they were removed from warhammer.com, I had hoped that they would remain. 

Units of the Mechanicum

Now this was a lot, and my goal was not to simply rewrite the book out for you all. So instead I will give a very high level overview of the units and some stand out considerations when you go through list building. 

High Command: 

• Arch Magos: 120 points. Great, love it. The unit entry is still extremely customizable (although the jump pack option is currently absent), making it easy to have this guy cost 200+ but if you have the points…
• Arch Magos on Abeyant: Take this one. For 30 points more you have a bonus to LD and T for a -1 to Initiative. Most importantly the Command Throne allows you reduce the cost of reactions based on an intelligence check. You will want this. 

Command:

• Magos: 100 points. Your Master of the Line. Giving two Detachment slots for the price of one. You will want to take a bunch of these, keeping them cheap to ensure you have the most flexibility in army building. No complaints otherwise, customizable, good stats, BS5 and a 2+ save. 
• Magos on Abeyant: If you want your High Command choice to be running around the map, have 1-2 of these guys in the backlines with Command Throne bubbles granting easier reactions.
• Arcuitor Magisterium: One of the rare examples of a Mechanicum unit with Infiltrate. WS6, S5, A5 make them a little melee blender of death but for some reason lack the Paragon Blade that the product description lists on warhammer.com

Retinue: 

• Scyllax Guardian Maniple: 100 points for a base unit of four. Great guardians (that is their job) with a 5++ invuln to shooting, WS and BS 5, and a 3+ save. Their weapons are AP3, Breaching on 5’s and considering you can have 16 of the three attack models in a unit… ouch.
• Echidnax Servo Maniple: The less deadly but more helpful repair automata. The more you have of them in the unit the better they are at Battlesmith. 

Veteran: 

• Domitar Battle Maniple: Can be taken in maniples of up to four (100 points a piece). They are fast, have seen a major buff in 3.0 (2+, 5++, but 4 wounds) and with both Vanguard and Impact (A), you will want them charging your opponents. 
• Myrmidon Seuctor Host: Now armed with a Power Axe and lacking Hatred, these little monsters feel a bit more balanced. In no way are these units “bad” with a Vanguard (3). Wipe your opponents captured objectives clean with these. 
• Myrmidon Destructor Host: Not cheap with each weapon other than the default Volkite costing as least 15 points per model. Still have Vanguard (3) and are effective. Both options are 150 points for 3 to start. 

Heavy Assault:

• Castellax Destructor Maniple: The robots with the fun guns. If you want to use a Multi Melta or a Darkfire Cannon you will need to use a Heavy Assault slot. They have Armour-breaker (4+) making them even more effective. 
• Ursurax Cohort: My favorite teddy bears of the 31st Millenium. Deep Strike, Vanguard (3), and a variety of effective weaponry. One less wound but you are paying 150 points for six versus 145 for three in second edition. Huge glow up.

Troops:

• Tech-Priest: The only option. Basic low level nerds that are an easy way to buff out units or enable your Automata to contest objectives when you give them the Cybernetica Tech Arcana. 30 points and 1 slot each. 

Support (but really your troops):

• Tech Thrall Covenant: T5 and a 6++ is nice but they still don’t do a lot of damage and now cost 100 points for 10 (but can go up to 40 models in a unit). While having expendable objective scorers is cute, they aren’t going to do anything else. You want to either skip them entirely or dive in, spamming the unit and then buffing them with Lacrymaerta Tech-Priests or Magos. 
• Thallax Cohort: 120 points for six with each model being able to exchange a Lightning gun for a special weapon. They move 10 inches but lack any special moving rules (beyond being Antigrav). They did gain the Aegis of Pain, providing Fear(1) when under effect of a Status. Photon Thrusters are rather spicy. 
• Castellax Battle Maniple: 100 points for two and BS3 (the same stats as their Heavy Assault option) the unit lacks a heavy weapon but replaces Armour-Breaker rule Firestorm allowing Volley Attacks to be at regular BS. With two bolters and a Mauler Bolt Cannon that is a lot of shots going into a charging or charged unit for 100 points alongside a statline that can weather return fire.

War Engine:  

• Thanatar Siege Maniple: Despite being called a maniple you can only take one… 225 points, slower, have 3 more wounds, and have some great kit (but probably worse than 2.0). They didn’t get the same treatment as Contemptor Dreadnoughts but given their difficulty to fit several into an army, they will be more rare. Naturally, the Calix is great at shooting into tanks. 
• Arminger Moirax: 165 points. Their S12, D3, Armour Breaker 5+, Breaching 5+, claws are awesome. If you take two then you are at S13, D5. 

Heavy Transport: 

• Triaros Armoured Conveyor: WIth the same transport capacity and a slightly slower statline (you will want to use a Quicken Status on them) you get two additional HP for 65 points and will always want to put them in an Iron Phalanx. 

Recon:

• Vorax Attack Maniple: 90 points for two versus 65 for 1. Five attacks on the charge and a movement buff makes these things pretty awesome. Being WS/BS3 make them prime targets for Status’ modifiers.

Fast Attack:

• Vultarax Stratos Squadron: A 1 model unit despite its name. Very different from 2.0 with the missiles getting better and the Arc blaster being worse. Cheaper but BS3 native makes them way less likely to hit. 

Armor:

• Karacnos Assault Tank: 10 points more for 2 more HP. The mortar is a status effect king and will continue to see a lot of play on the table. 

• Krios Battle Tank: All vehicles do have a Auto-repair (4+) which is very appreciated. When paired in an Iron Phalanx these tanks are Front Armor 14, Side Armor 13, and 7 HP which will really change how easily they can get thrown around the table (in your favor). Two profiles. This lets you choose between the Lighting Cannon (its fine) and the Irradiation Blaster (fun but no longer having the cool beam effect) and another profile…
• Krios Venator: 160 points base (25 more than their siblings) but Pulsar Fusil rocks. No other notes but equally impressive in an Iron Phalanx. Two shot, D3, Strength 9, AP2 shots that also have Suppressive (2). 

Machina Malefica: 

• Decimator: 125 points and very similar to the Contemptor dread. Being 25 points cheaper for one less inch of movement, 1 less Wound, Initiative, and 4 less LD but an Automata versus a Walker. Instead it gains Vanguard (2), Impact (A), and Firing Protocols (2). 
• Blood Slaughterer: 2 for 100 points. 6 attacks on the charge and Vanguard (1). These have some play but a base WS of 3 means you will want to buff it. 
• Brass Scorpion: 600 points and 15 wounds of death! Notable for being Unstoppable meaning that it doesn’t get stuck in a melee and can keep trucking on. Its claws are AP2, D3 with a bunch of bonuses at S10. Its guns are great. This thing rocks. But it is 600 points… 
• Kytan: Also Unstoppable at a small 450 points. With a pinning cannon and a deadly axe this thing is also a lot of fun and benefits from being an Automata vs a Knight.  

Persona Scindio: 

• Archmagos Scoria: 410 points of Xana excess. He has a unique mix of Cybertheurgic Rites, Fear (2), along with the Champion Subtype. His statline is great and the Vodian Scepter is basically “Status (everything)” with Shock (Pinning, Stunned, Suppressed).
• Archmagos Draykavac: With an on foot and on Abeyant option (200 and 220 points), he comes with his own mix of Rites, a unique Gambit (letting you shoot your opponent with a nasty weapon that has Phage (T,S)), a great way to start a challenge. When out of combat he can choose to remove himself from battle (based on a cool check), making sure your opponent does not get points for slaying him. 

Final Thoughts

Well there you have it, the Liber Mechanicum. This was a long one but given the volume of changes in the book and faction, it felt necessary to complete this exhaustive Deep Dive. This book is great, perhaps the highlight of the edition launch and going through this process has made me even more confident in that. I would argue this is a better and more interesting faction than the Astartes in its current form and I welcome you all to give this army a go! I cannot wait for the hypothetical Dark Mechanicum sibling and the variety of forces found on tables world wide. 

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