Designer’s Note: The following is a refresh of the official Blood in the Void expansion released by Games Workshop in The Horus Heresy: Book Three - Extermination (May 2014), which is no longer in print. Modifications to the rules described below have been done to adapt the fantastic work of Alan Bligh to Second Edition.

Introduction

This section presents rules for fighting some of the most savage and desperate ship-to- ship boarding assaults of the Horus Heresy. Boarding actions between star vessels are truly deadly affairs, vicious and swift close- quarter duels in the most treacherous and dangerous environments imaginable. In short, the kind of conflict the Space Marines were created for!

The vessels of the 30th Millennium range in size and role from interplanetary cargo scows to mighty battleships with crews numbering in the thousands serving as the flagships of the Imperium’s far-ranging Expeditionary fleets. Larger still are Mechcanicum mass conveyors tens of kilometers in length, and unfathomably ancient drifting space hulks that dwarf even these. In the case of these larger vessels, regardless of whether they are an engine of war or a colony ark, their sheer size grants them weaknesses to be exploited, just as their immense bulk makes them difficult to destroy by more conventional means. For these mighty ships, damage to specific systems can be as fatal to them as poison injected into a living heart. The best way of doing this is often by breaching the hull of an enemy vessel and assaulting it with troops - if they are victorious then the ship may be crippled, captured intact or even destroyed from within.

Only the most skilled and able warriors are selected to undertake boarding assaults and attrition among them is always high, as is the glory gained should they succeed. The shipboard defenders who repel a boarding assault must fight with all the courage and ferocity they can muster if they are to save their vessel. For the loser death is certain, as aboard a star vessel surrounded by the infinite darkness of the cold and silent void, there is nowhere to retreat or run to.

Terrain & Board Construction

In Boarding Assault games, the terrain and unique nature of the battlefield is of particular importance. The area of conflict represents the internal spaces and decks of a mighty star vessel rather than ground terrain, but what this means in practice can vary immensely depending on what part of the ship is being fought over. The majority of Boarding Assault missions are fought along the cramped companionways of the vessel’s interior, best represented using the Necromunda Zone Mortalis Terrain Set and accompanying Gameboard Tileset . The availability of these tiles has made it possible to create thematic rules appropriate to the terrain and setting, but players using terrain of their own creation may find they need to alter the rules given to take their own scenery into account. Note that where the rules refer to a Zone Mortalis tile, they are referencing a 12” x 12” section. Where players are using terrain of their own devising, simply divide the table into a grid to determine the area in question.

Other battles might be fought across far more open areas, such as cargo bays, launch decks, reactor chambers or even the lush arboretums carried on some colony arks. In these cases, a mix of Zone Mortalis Multi-Level Terrain and more conventional terrain can be used, or in the case of a shipboard Arboretum, areas of vegetation mixed in with the void ship terrain. In such cases, most of the rules presented here still apply, but players may have to adapt them to the specifics of their terrain. As always, let the narrative which you are forging together take center stage when deciding what terrain makes sense to use.

Outer Hull

The expanse of a gigantic ship’s outer hull can itself form a battlefield, and some of the most desperate and bloody boarding actions are fought simply to force a breach in a ship’s armored flanks. In boarding actions of this kind, the outer surface of a ship forms the battlefield you are playing on, with attackers seeking either to force airlocks open or damage vital structures on the hull’s surface. Terrain on an outer hull table should be sparse, covering no more than a quarter of the table’s area in total and should be made up of large regular structures and objects, along with antenna, gun towers and other forms of machinery representing the ship’s systems. Obviously, no natural terrain or anything ‘loose’ to the ground should be used.

When fighting on a ship’s outer hull, the Cold Void special rules are always in effect. In addition, any blast attack that causes a Pinning test has a chance to send its victim spinning helplessly into the void! Instead of causing a Pinning test, any model caught in the blast who survives must pass a Strength test or be removed as a casualty (a roll of a 6 is always counted as a failure). Infantry sporting Jump/Jet Packs may re-roll this test if it fails. Jump Infantry may move according to their usual rules, but when activating their Jump/Jet Packs in any Movement Phase, they must make a Dangerous Terrain test. Models who fail the test are lost to the void and removed from the table as a casualty.

Cold Void: When this special rule is in effect, the following conditions apply to the region:

  • All weapons and attacks with a Strength of 6 or higher now cause Shred, unless their target has the Heavy Subtype or has an Armour/Cover Save of 2+.
  • Weapons and attacks which have the Blast special rule also now cause Pinning if they did not already.

Catastrophic Damage Table

Most boarding actions take place against the backdrop of a fierce void battle in which immensely destructive forces quite beyond the combatants’ control are unleashed that may even destroy the very ship through which they are fighting. Even when the boarded ship is not taking direct hits in the battle, the effects of prior damage can cause secondary explosions to rip through its hull or the vessel itself may be caught in a crossfire or ride through the blast waves of dying ships and lethalJy spinning debris.

These effects are represented in the game by the Blood in the Void - Catastrophic Damage table (shown below). When the Catastrophic Damage special rule is in effect, in every successive Game Turn after it is activated, each player should roll a D6 each at the beginning of the turn. Add the scores together and apply the results on the Catastrophic Damage chart on the next page. In addition, if any weapon with the Ordnance special rule has been used on the preceding turn, add +1 to the total. Note, that this special rule brings a hugely unpredictable (and enjoyably dangerous) element to your games, and should be treated as such.

2D6 Result Name Description
2 - 4 Stable Although the hull cracks and moans with the sounds of distant thunderous explosions filling the air, the effects are not strong enough to play a part in the Battle this Turn.
5 - 7 Power Surge The ship’s energy systems go into violent spasm, blowing out lighting arrays and either plunging the area into darkness or flooding it with a blaze of blinding sparks. If this result is rolled, then the Night Fighting special rule is in effect this turn. If they were already in effect, they no longer apply this turn. Additionally, if they are being used, bulkhead and airlock doors may either open or shut on their own on a D6 roll of 5+ (rolling once separately for each one.
7 - 8 Hull Quake The ship’s hull bucks and shakes, causing the gravity field to fluctuate wildly. For this Game Turn, all clear terrain is counted as Difficult Terrain, all Difficult Terrain is treated as Dangerous Terrain, and all Dangerous Terrain explodes (dealing a Strength 5 AP 5 [Pinning, Rending (6+)] Attack to all models within the Terrain feature).
9 - 10 Wildfire A series of secondary explosions brackets the area of the battle as conduits erupt into flames and areas of the deck plating collapse or are blown in. The players roll off and the winner may place 2D6 Large Blast (5”) templates anywhere on the table. Each explosion Scatters 3D6” from the target point. Any model caught under a template suffers a Strength 5 AP 5 [Pinning, Rending (6+)] attack.
11 Depressurization The players roll off and the Winner indicates an area of the board entirely bound by walls and/or door sections. Any doors in this area immediately close if they were open and the area becomes subject to the Cold Void special rule for the remainder of the game. Should any door bounding the area be opened or destroyed, the effect extends to the adjacent area as far as the next set of walls and doors, which themselves automatically shut. Needless to say, players will have to use common sense to define the exact extent of any areas that become subject to this special rule.
12 Structural Collapse The hull screams and shudders before part of it catastrophically fails and breaks apart, either blasting out air and debris into the beyond or shattering around the unfortunate combatants. The players roll off and the Winner indicates a single Board Quadrant of their choice. All models with a Toughness value in the affected area suffer an immediate Strength 4 [Rending (5+)] hit, and models with an Armour Value (including special terrain, and so on) suffer a glancing hit on 4+. In addition, the Depressurization effect described in the previous result comes into play.

Boarding Assault Sessions

A ‘Hit & Run’ attack is a crucial tactic used in ship-to-ship combat and involves one or more boarding parties forcing access to the target ship, fighting their way through the companionways with the aim of destroying key systems. Boarding an enemy vessel with the aim of destroying, crippling or capturing it is a grueling task and one that will exact a high price in blood from both attacker and defender over a number of savage battles.

From the initial breaching attack to the ship master’s final stand on the bridge, many different types of battle are possible. Furthermore, several games can be linked together, allowing players to determine the fate of the ship and of the courageous boarders. These linked battles can be thought of as a short but bitterly fought ‘node-‘ or mini-campaign that can easily be played over the course of a single day or weekend, depending on the number and size of games the players wish to engage in.

Enemy Unknown: This optional special rule is designed to mimic the confusion when even the finest auguries and sensors are jammed, with only the minimal intel of the ship’s schematics to work with. Each player is required to bring a set of numbered counters to represent “blips” on the auspects, which are sufficient for the number of Units (not Models) it has in its force. Each number must correspond to a particular Unit within their force, which must be noted down before the game begins (the note kept secret from your opponent for now). It is these counters which are deployed rather than the Units on the table.

As the game progresses, the “blip” counters are moved in place of Units until they move within Line of Sight of an Enemy Unit or the Unit Engages in a Shooting or Close Combat attack. At this time, the Unit is revealed and the note showing the number and its corresponding Unit is shown to the opposing player. The “blip” is then replaced with the corresponding Unit, which is deployed in coherency with its centre where the Counter was when revealed. If on subsequent Player Turns, a Unit that has revealed itself passes out of Line of Sight of the opposing Force’s models, it is once more replaced with its corresponding number counter (and it is up to the enemy to remember what it was until it becomes visible again).

Independent Characters which join Units do not have a “blip” counter of their own while they are within a Unit, but this fact must be always noted down to avoid confusion or chicanery! If the Independent Character leaves the Unit, they gain their own “blip” counter. Ad-hoc Units of Independent Characters are considered one Unit so long as they are joined together for the purposes of how to represent them as “blips”.

Performing a “Hit and Run” Action

To play through a “Hit & Run” attack, the Players should decide narratively or randomly determine who will be the Attacker and who will be the Defender. The target vessel’s size determines how many battles must be fought to capture it or destroy it, and which Mission Goals are used in each mission being played. A suggested Mission breakdown is provided below for three types of ships common during the Horus Heresy. Victory earns the winning player a single ‘Boarding Point’, used to track the overall damage done to the target warship and its defenders. Once the indicated Wrecking Missions are all played, both sides compare the Boarding Points they have earned to determine their position in the final Salvation mission.

If the Attacking side is in the lead before this final mission, the vessel is in flames and doomed to a fiery death in the void, and the boarders are attempting to return to their assault boats or teleportation points and away to safety, secure in the knowledge of their victory.

If the Defending side is ahead in points going into the final game, the boarders have been repelled and the vengeful defenders are chasing them down through the bloodied companionways.

This system ensures that the results of each mission feed into the last game, but that the ultimate victor of the Hit & Run attack is not determined until the end of that mission. Even once the ship’s death or survival is known, only once the Salvation mission is played are the players able to determine the ultimate fate of their resolute defenders or bold attackers, giving a satisfying range of results to the series of games. This gives four ultimate end results-the attackers might win a pyrrhic victory by destroying the ship but then perish along with it. The boarders might destroy the ship and escape to safety. The attacker might be repelled and the ship saved but nonetheless escape to fight another day, or the boarders might be fought off before being hunted down and slaughtered.

All or Nothing: This option is provided to add an additional level of tension to the boarding operation and should only be used at the instigation of the Attacking player with the agreement of the Defending player. If chosen, the Attackers mount an assault via the ship’s outer skin, the aim being to cut through its armour and gain direct access to an especially viral area without the need to fight through kilometres of companionways and then all the way out again. Success means the attackers destroy the vessel and extract without further loss. Failure means the certain death of the Attackers as they are repelled, cast out into the cold void.

If this option is used, the All or Nothing special mission is played. The winner of this mission is the winner of the whole series of games, with no further games being played. Fortune favours the bold!

Target: Escort Frigate

When conducting a “Hit & Run” against an escort-sized warship, three Boarding Assault missions are played:

  • Mission 1: Void Strike
  • Mission 2: Wrecking Mission
    • Roll a D6 for the Mission Goal …
      • Result of 1-2 –> Drives
      • Result of 3 –> Augur Arrays
      • Result of 4 –> Weapon Batteries
      • Result of 5 –> Life Sustainers
      • Result of 6 –> Ship’s Bridge
  • Mission 3: Salvation

Target: Cruiser

When conducting a “Hit & Run” against a cruiser-sized warship, five Boarding Assault missions are played:

  • Mission 1: Void Strike
  • Mission 2: Wrecking Mission (Goal: Drives)
  • Mission 3: Wrecking Mission
    • Roll a D6 for the Mission Goal …
      • Result of 1-2 –> Augur Arrays
      • Result of 3-4 –> Weapons Batteries
      • Result of 5-6 –> Life Sustainers
  • Mission 4: Wrecking Mission (Goal: Ship’s Bridge)
  • Mission 5: Salvation

Target: Battleship

When conducting a “Hit & Run” against a battleship-sized warship, seven Boarding Assault missions are played:

  • Mission 1: Void Strike
  • Mission 2: Wrecking Mission (Goal: Drives)
  • Mission 3: Wrecking Mission (Goal: Augur Arrays)
  • Mission 4: Wrecking Mission (Goal: Weapon Batteries)
  • Mission 5: Wrecking Mission (Goal: Life Sustainers)
  • Mission 6: Wrecking Mission (Goal: Ship’s Bridge)
  • Mission 7: Salvation

Mission Compendium