" differences in horus heresy 2nd edition, part 1"

Just a heads up, there are many, many changes in this new edition of Horus Heresy and some of them aren’t obvious at first. its easy to overlook changes to existing special rules that retain the original name from 1st edition.

I must also give a warning here to anyone that picks up the new rule book, in good old Games Workshop fashion, the layout is terrible and you will find yourself flipping back and forth between pages to find rules.

So, lets dive into the new core rule book to have a look at the rules changes.

Core Rule Book Contents

The first chunk of this massive 334 page book is taken up by story sections and miniature galleries. The actual core rules kick in at page 146.

Core Rules.

  • Unit profiles. 
  • dice, scatter dice and template rules.
  • Turn sequence- move, shoot, assault.
  • Morale, fallback.
  • Reactions, advanced reactions.

Unit Types.

  • Most standard types, plus some sub types.
  • Characters.
  • Psykers plus core psychic disciplines. 
  • Vehicles, armour facings, damage tables and vehicle types.
  • Super heavies.

Battlefield Terrain.

  • Terrain types including difficault and dangerous.
  • Buildings and damage tables.
  • Basic fortification datasheets.

Special Rules.

  • A large section of universal special rules.

Gaming In The Age Of Darkness.

  • Mission rules.
  • Allies.
  • Objectives.
  • Battlefields


The movement phase has seen some of the most changes, the first being …… every unit has its own movement stat now. Your base Legion marine has a movement of 7. So always check your units movement on the data slate.

units can Run as an additional boost to moving, rather than shooting. Running is standardised – it’s in the Movement phase (not the Shooting phase as in the previous edition) and you increase your Movement Value by your Initiative Characteristic (Giving your Legionaries a run of 11 inches).

Dangerous Terrain is now actually dangerous, and much more deadly than it used to be. If you move through Dangerous Terrain, roll a D6 per model. On a 1, it suffers a Wound with Invulnerable saves only! (no Damage Mitigation saves such as Feel No Pain). This is brutal, and can be used to your opponents advantage to funnel your troops.


Shooting Phase

Shooting is still a chart, your ballistic skill signifies what you hit on.  BS 4 hits on a 3+ etc

Wound allocation is now very straightforward:

  • You fire and sort out wounds “weapon by weapon” in a unit .
  • Roll all hits for the Weapons which are firing; 
  • Roll the Wounds (using majority Toughness); 
  • Create a pool of any Wounds;
  • The player being shot at then selects any model in the unit being shot at (it doesn’t have to be closest first, but they have to be in line of sight and in range, and if it’s a multi-wound unit then it has to start with wounded models); 
  • You roll saves until that model dies, and move onto the next one. 

Look out sir roles and tanking hundreds of saves on a sergeant with artificer armour are gone! which is a good thing as it often slowed the game down.

Assault Phase.

Charging is simple, pick a target, declare a charge, roll 2d6 and add any bonuses you get.

its still possible to fail a charge but you now have a surge move. If the 2d6 wasn’t enough to get you into combat, you move half the distance rolled, rounding up towards the target.

The other major change is to the Weapon Skill table. You can now potentially hit on a 2+, which never used to be the case before, if you outmatch your opponent sufficiently (e.g. WS 5 vs WS 2). The big one, however, is that WS 4 hits WS 5 on a 5+, as does WS 3 v WS 4. I cannot overstate how big this is, potentially. 


The Morale system has not changed – you still take Morale Checks at the end of combat on 2D6 for example, needing equal or under Ld, or if you lose 25% of your models in one phase. Falling Back still works in the same way (2D6 flee towards your table edge), and Pinning is more or less the same, with the new nuance that you cannot do Reactions if Pinned (can’t move, React, or charge for a turn, Snap Shots at BS 1 only). 

Marine Legionaries are now Leadership 7, and Sergeants are 8. This means, if your Sergeant dies, any negative modifiers to your Leadership (even if just -1), means you are more likely than not to run away or get Pinned.

Psychic Phase

In 2nd edition the psychic phase has been removed, you now cast powers when indicated on the data entry.

You start by picking a Psychic Discipline (one, or more, depending on the unit), and then you get all the powers in that discipline automatically, along with the power Aetheric Lightning, which is basically Smite. 

Each Discipline has a handful of powers. These are cast differently to before. There is no Psychic Phase – instead each power has a moment in which you can use it, which is set out in the power’s profile. 

To “cast”, usually it’s just a Leadership check (2D6, equal or below your Ld value), and if you fail you take a Perils of the Warp, which is simplified from before to D3 Wounds with Invulnerable saves only (no Feel No Pain, for example). 

Some powers you don’t have to take a check for – they are “cast” automatically, but you can choose to take a check (with the corresponding Perils risk), to improve the power in some way. 


The biggest change to the game!

A Reaction is an ability which allows a Reactive Player to take an action in their opponent’s turn. This existed in the previous edition in a limited way – for example, Overwatch. It is now fleshed out and the Legions all have flavourful unique Reactions as well. 

Each player has a Base Reaction Allotment. This is 1 Reaction per phase of your opponent’s turn – so one in the Movement, one in the Shooting, one in the Assault. 

ou can increase the Base Reaction Allotment with some powers and abilities. If this happens, you will go up to multiple Reactions per phase (very powerful), up to 3 maximum per Phase (outside of specific circumstances).

More common are special rules which, instead, increase a specific phase’s Reactions – e.g. allowing you to do 2 Assault phase Reactions. 

You cannot do a Reaction if you are Pinned or Falling Back (see our Morale discussion above – a key thing to think about if you wish to disrupt your opponent), or if you have already done a Reaction in that phase with that unit. 

Each Legion then has a Legion-specific Reaction, but the most common ones which will be used are the Core Reactions:

We will go over the reactions in a separate article.

we will jump straight back into it ” differences in horus heresy 2nd edition, part 2″ starting with Unit types.