Ye Old Ruleshammer: Armour Value and Plague of Rust

Welcome back to yet another instalment of Ruleshammer for Warhammer The Old World. In today’s segment we’re taking a look at what armour values are, how they’re modified, when you use which one, and some strange interactions. 

What Is Armour Value?

In short, a model’s armour value is the save that it gets to make protecting it from attacks. This is determined by the armour worn by the model or more simply by a value shown on a model’s profile; the latter is often reserved for chariots or other mixed-profile models. Armour values include regular armour saves, ward saves, and regeneration saves.

Determining a model’s armour save is otherwise simple:

  • Light armour: 6+
  • Heavy armour: 5+
  • Full plate armour: 4+

Other gear goes further improves the save by a further +1 increasing the above save values, these are:

  • Shields
  • Barding

An armour save can only be 2+ at best regardless of any other combination of rules a model might be able to come across. Some magical items can increase saves further so be mindful in list building if that will even make a difference before purchasing!

A model however cannot use a shield while it’s also using a weapon that requires both hands, such as great weapons or paired hand weapons. In the first round of combat a model can choose what equipment it will use and must keep using the same option so long as that combat is ongoing. If that model is carrying a magical weapon then there’s no choice and it must be used at all times; a model wielding a magical two handed weapon would not be allowed to choose to use a mundane weapon and shield.

Does that mean shields are pointless on models with two-handed weapons? No! They still confer +1 save from shooting attacks and with a Ruby Ring of Ruin in every list that extra save is invaluable.

Ward and Regeneration

These are both also a type of armour value but are not effected by the bearer’s armour or negatively modified by the AP of enemy attacks. Where a model has either (or both) will be clearly stated on their sheet. You also get to try and make these saves after armour and after each other, too. The order of saves you get to attempt are:

  1. Armour Save
  2. Ward Save
  3. Regeneration Save

In that order very specifically, if you have them, if you’ve failed the previous save. The only difference is that any wounds saved from Regeneration with still count towards your enemy’s combat resolution score; successful armour and ward saves do not. So keep careful track of what saves were made and not just of models removed!

Split Profiles

Some units are made up of a mix of models that wear various kinds of armour, carry shields, etc and have a “split profile”. Units that are like this will just have an armour save denoted such as Tomb Guard Chariots having a 4+ save regardless of the crew using shields or not; it keeps things simple for both players and means they can attack with their two handed halberds without penalty, too!

Ridden Monsters become more complicated and now we have to look at a few rules and the April FAQ to see why there’s ongoing confusion. There are two camps of thought on this and if you’ve spent any amount of time online you’ve seen both arguments.

First we turn to page 204 of the Core Rulebook:

When this model makes an Armour Save roll, it may use either the mount or the character’s armour value, whichever is better.

Seems exceptionally straightforward: when determining which armour value to use for the armour save (that’s only step one of the above types of saves) you use the better value. Thankfully armour values are very simple and is just a number whether that’s 4+ or something else. What is “better” is the lower number. A 2+ is the best you can get, 6+ is the worst (aside from no save at all!). This isn’t a choice, either; you’re told to use whichever is better.

A Bone Dragon no-long re-rolling successful wounds against it. Credit: Bair

Now with magical armour in the FAQ from April 2024:

Q: A character mounted on a ridden monster or a chariot can choose to use their own or their mount’s armour value, whichever is better. If the character wears magic armour but I choose to use the mount’s armour value, can I still claim other benefits conferred by the magic armour?
A: No. You must use a magic item fully or not at all.

This FAQ directly nerfed a number of suits of armour that were being combined with monstrous mounts like dragons, resulting in no longer being able to stack magical armour abilities with the mount’s often better save.

That wording in the question part is now causing some confusion, however, by making the part before sound like it’s the player’s choice which save they use; whether that’s the better mount’s save without the magical item or is the worse save combined with the magical effects.

My take on this is that the FAQ is not changing how you determine the save at all. You still use the armour save that is “better” as determined solely from the number of that save, not any other abilities if may confer. Some believe that the wording “may use either the mount or character’s armour value” is a choice. If I were to make you an offer and say you “may take either the blue or red box, whichever is larger” you would take the larger one, not assume that you arbitrarily choose which one to take. While the wording in the question of the FAQ is frustrating, the “choice” being made isn’t the player’s choice but telling you which has been chosen based on the “whichever is better” rider.

Let’s use the Armour of Ages from Tomb Kings as an example, a piece of Light Armour conferring the normal 6+ armour save. The effect of the armour is for all successful wounds against the model to be re-rolled, an expensive effect for a Tomb King on foot or simply on a steed but usable. On a Bone Dragon (armour value 4+), however, it’s a very expensive piece of equipment that doesn’t do anything because you’re forced into using the Bone Dragon’s better armour value. Mathematically re-rolling successful wounds might work out as “better” than a lower armour save and that doesn’t matter, only which armour value is better matters for this. This gives the Armour of Ages and unique place however in being very useful on a Warsphinx mount, so long as you give the King a shield, giving both rider and mount 5+ armour values; just don’t also equip the King with a two-handed weapon! Similarly useful on a Chariot keeping your King (also immune to Killing Blow and Monster Slayer here) harder to take down.

Be careful during list building that you aren’t spending points and taking items which your character will not be able to make use of!

A simple wizard about to cause some incredible havoc and start arguments. Credit: Bair

Plague of Rust

Easily the most contentious spell of our time! The first time I read this it seemed very simple, more the fool me!

A hex spell that casts on a 9+ with a 21″ reach it’s pretty easy to cast any turn after the first in most deployments and does:

Until your next Start of Turn sub-phase, the target
enemy unit suffers a -2 modifier to its armour value. This
spell may target an enemy unit engaged in combat.

It’s not even a lengthy spell either! The contentious part is that it uses “armour value” instead of saying that the “armour save” of the effected unit is modified. That means that both Ward and Regeneration are also modified by -2 because they are armour values. This seems incredibly odd but is correct. On one hand this tones down big monsters a lot and on the other it just isn’t very intuitive, especially to returning players.

That said the majority of people that I know have looked at this and basically said “we aren’t doing that, right?” and I generally agree that it is a bit ridiculous.

Best Practice for Gaming

That all said I can understand confusion around rules and that people will simply not want to play the “correct” way always. In any case the best practice is just to talk to your opponent before your game or with the organiser of an event you’re attending to make sure how this, and possible other rules, are being dealt with.

How are your play group dealing with these rules? Let us know in the comments below or email in to if you have any questions.