The Dark Fortress

Mind Wipe and walkers and rules interpretation

5 February 2016 | 7th Edition

A Dark Angels Librarian, yesterday.
Oh! What happens next?
Photograph from

So an interesting topic cropped up on the excellent Bolter & Chainsword forum regarding Mind Wipe and walker units. What happens? Initially a rules issue but what fascinated me was the wide variety of differing interpretations that were put forward as the answer.

We need to remind ourselves what the actual rule regardng Mind Wipe is (page 156 Dark Angels Codex):

Mind Wipe is a malediction that targets a single enemy unit within 24". All models in the target unit have their Weapon Skill and Ballistic Skill reduced to 1 until the end of their next turn, at which point the unit must take a Leadership test. If the Leadership test is failed, the effects of Mind Wipe last for the rest of the game.

and a quick look at Malediction itself (page 27 of the rulebook):

[…] Maledictions target one or more enemy units and, unless otherwise stated, last until the start of the Psyker's next Psychic phase. […]

The issue being that walkers (and indeed all vehicles) don't have a Ld value. And for some this is where the haziness creeps in. Various answers were put forward — some of them really not applying any logic that could be derived from the rules as they are written.

The question

Here was the question that the poster kicked off with:

The simple question is this, What happens if I cast Mind Wipe on a Walker (or Superheavy Walker)?

Here were the possible answer options suggested by the same poster:

  1. The Walker has its WS and BS lowered to 1 it is required to take a leadership test, then it automatically goes back to its normal stats
  2. The Walker has their WS and BS lowered to 1 until they are required to take a leadership test, then due to not having a leadership score, automatically fail it and are at WS/BS 1 for the remainder of the game?
  3. The Walker can not be targeted by Mind Wipe because they do not have a Leadership stat
  4. Something else entirely that I can't even comprehend.

The solution options listed above were influenced by this reasoning:

  1. Psychic pilot states the vehicle behaves as having Ld10 for all things that deal with psychic powers. However in this example I'm targetting a walker without the pyschic pilot rule. Is this enough precedence to say that ALL vehicles behave as Ld10 when dealing with psychic powers?
  2. [Quoting from the rulebook]"It is assumed, in all cases, that the crew’s faith in their vehicle, and its considerable armour plating, is absolute." Therefore, vehicles never take morale checks or leadership tests.

The answers

Without identifying anyone, here were the answers that were subsequently posted:

Answer 1

Mind Wipe clearly says that a targeted enemy unit can be afflicted by the Malediction. A vehicle, unless joined by a monster or infantry/beast/cavalry can't be counted as a unit. It is a model or vehicle or squadron. Therefore an Imperial Knight can't be afflicted by wipe.

Answer 2

Play as if they are Ld10. That's how I do it.

Answer 3

I may be quoting a past edition, but I seem to remember that vehicles count as Ld10 for the purpose of Leadership checks. Vehicles do not need to take Morale checks (they count as Fearless), but they are still subject to Leadership tests.

and in answer to a similar question posted on another forum:

Answer 4

[…] I think that vehicles would auto-pass morale tests though which makes targeting them with Mind Wipe pointless.

Answer 5

[…] my opponent claimed his vehicles could not be targeted by the power since they don't have a leadership score.

There are a few common misconceptions creeping in there that aren't based on the current ruleset. Some of the answers are worryingly hilarious, if that's a thing.

The correct answer and why

At last, we get there.

Vehicles as per page 78 of the rulebook [on vehicle leadership and morale], never take morale checks or Ld tests. The confidence of the crew on the armour plate is absolute.

The only exception is that a vehicle with psychic pilot (rulebook page 170) uses a Ld10 for his psyker tests.

So what does this mean?

Mind Wipe can in fact reduce BS and WS of a vehicle or vehicle unit.

But Mind Wipe will never be permanent. As vehicles have no Ld you either assume they pass the Ld test automatically, or the Ld test can't occur at all because they have no Ld to test against. This is independent of any Psyker pilot rules.

So why was this the correct answer to the original question?

As ever it's a question of dividing the rules as written up and considering whether each are capable of being implemented. Something like this:

  1. Psychic Pilot is no precedent for vehicles that don't have it
  2. Mind Wipe reduces WS/BS until end of next turn. This rule can be implemented.
  3. As vehicles don't take Ld tests therefore they can neither pass or fail one. So that part if the Mind Wipe can't be implemented.
  4. Malediction powers only last until the start of the psykers next psychic phase (rulebook p27). This Malediction rule can be implemented too.

So overall we end up with reduced WS/BS only lasting until the end of the next turn (DA Codex trumping rulebook Malediction here).

But what do you think?

This wasn’t a particularly tough nut to crack. The irony is the poster had the answer in his grasp but just didn’t know it (or merely wanted it reaffirmed).

As demonstrated, there’s also the common danger of remembering rules from previous editions and throwing them into the mix. It’s as though we ourselves need to be mind-wiped, or reset, at the start of every new edition of anything.

Happy gaming