Intro

Background

Have you ever been curious what would happen if a Dwarf throng were to come face to face with an Eldar raiding force? A Company of Space Marines dropping in only to find itself surrounded by Dragons? What about an Empire Army marching north, expecting roving bands of marauders, only to come face to face with a Chaos Space Marine Warband?

I have.

In 1988, Games Workshop published Warhammer Siege, which allowed players to lay siege to each others’ castles on the battlefields of the Old World and the far future. It provided context, plot hooks, and additional equipment for all manner of that specific type of warfare. Indeed, it’s in that august publication that the inspiration for this document comes from – specifically, the ‘Sieges in the Far Future’ chapter. In it, there’s a section called ‘Types of Siege’, detailing how players might be able to mix their Warhammer 40,000 and Warhammer Fantasy units in a single game to represent a variety of scenarios. Examples include a Space Marine garrison being attacked by a primitive Orc horde, or an Imperial force having to rescue an inquisitor who’s been captured and held in a dungeon by the primitive locals.

This sort of game hasn’t really been possible since the first edition of Warhammer 40,000, since the mechanics of both 40k and Fantasy started branching off quite dramatically from one another in the early 1990s. Now, however, Warhammer 40,000 in its 8th edition and Age of Sigmar in its 2nd edition are remarkably similar as gaming systems, which I hope you’ll see as you read through this document.

Though there are enough differences to give a rewarding experience for someone who tries both, both Warhammer 40,000 and Warhammer Age of Sigmar have benefited from vastly simplified rules systems than their predecessors. This, in turn, has left them as two core systems that, with some modifications and the proper spirit, can easily be played together.

Rules Goals

The goal of these TOTALLY UNOFFICIAL rules modifications is to allow both 40k and AoS players to play their own army – that is, play their own familiar rule set and datasheets, without having to significantly rewrite both 40k and AoS. I’ve tried to add rules and abilities where appropriate, rather than taking them away (see Delta Vector’s excellent article on negative game design here). It would be far less satisfying as a Space Marine player to suddenly find their boltguns have a 12” range! Rather, balance is attempted primarily through points adjustments (i.e. AoS Players pay half), scenarios, and unit abilities.

Please note that these modifications are intended for fun games with friends, not exactly intended for competitive play.  If you use these, please do let me know how it goes in the comments, I’d love to see how you got on!

Theme ideas

Below, you will find a few ideas for scenarios covering why forces from the two game systems might come into conflict.

Warhammer 40,000:

• An Imperial Explorator fleet led by Rogue Trader Erasmus De Villius encounters a planet ruled over by a group of lithe, low-tech Aeldari devoted to the god Khaine. These ‘Daughters of Khaine’ don’t initially appear outwardly hostile, but as emissaries and envoys keep going missing, only to turn up disembowelled or worse, hostilities quickly escalate. Eventually, it is revealed that these Aeldari are a blood cult, employing dangerous mutant versions of their sisterhood, including poison archers with the lower bodies of snakes. The planet must be purged.
• A Chaos fleet is becalmed in a region of the Cicatrix Maledictum, only to come under attack by strange reptilian daemons made of pure light, led by bloated frog-like creatures riding stone palanquins.
• The Ocean World of Eorla is suffering. All along the coasts, settlements fall silent, their populations discovered irrecoverably comatose or mysteriously vanished altogether. An Inquisitor requisitions a force of the local PDF and goes to investigate. Soon after entering the water, they come under attack by a force of Aeldari riding various sea creatures and wielding strange, psychically-charged primitive weapons

Warhammer Age of Sigmar:

• The Eye of Terror in the Realm of Chaos spews forth a horde of strangely armoured Warriors of Chaos, stronger and bigger than any the foul legions of Chaos had heretofore known. These warriors claim to bear the word of Chaos to all corners of reality, and their Dark Apostle gathers forces from the realm to him. They lead a crusade out into the Realm of Chamon, corrupting and despoiling as they go. They are confronted by a mixed force of Kharadron Overlords, Fyreslayers, and Stormcast Eternals, who are determined to stop this dark crusade.
• The constellation of Tarmus in Azyr is attacked by a vaste horde of cosmic horrors – a leaping, chittering horde of monstrous insectoids bent on devouring all life. The entire Celestial Purifiers Stormhost is sent to halt the horde in its tracks.
• The Ironweld Arsenal in the Freeguild City of Chadia quickly becomes famous for its technological innovations, creating a variety of weapons of war, from handguns that fire a concentrated, searing beam of light, to steel behemoth tracked vehicles capable of mounting the heaviest cannons. Instead of sharing this technology with their allies, however, Chadia quickly turns insular, refusing to cooperate with other Free Cities or the forces of Azyr. Thus, when the forces of Chaos hear about their technological marvels and attack, Chadia stands alone.

Turn Sequence

Battle Round Modifications

A Battle Round is modified to be as follows:

1) Initiative Phase*
40k Player Turn	AoS Player Turn
2) Movement Phase	2) Hero Phase*
3) Psychic Phase*	3) Movement Phase
4) Shooting Phase
5) Charge Phase*
6) Fight/Combat Phase*
7) Battleshock Phase

*indicates a new or modified phase – see below for details

Player Turn Modifications

Initiative Phase

In the Initiative Phase, both players roll-off, and the winner decides who takes the first turn. If the roll-off is a tie, then the player who went first in the last battle round can choose who goes first in this one, but if it is the first battle round, the player that finished setting up their army first chooses who has the first turn.

Psychic & Hero Phase

AoS WIZARDS may attempt to dispel 40k Psychic powers as if they were spells. Likewise, 40k PSYKERS may attempt to dispel AoS Spells as if they were Psychic Powers. For consistency, 40k Deny the Witch Tests have the same 30” range as AoS unbinding.

Charge Phase

After a charging unit declares its target(s), the unit that the charge is declared against may immediately fire Overwatch at the wound-be attacker. Use the rules from Step 3 – Overwatch of 40k’s Charge Sequence for both AoS and 40k units.

Fight & Combat Phase

These phases are synonymous – both 40k and AoS players with models within 3” of an opposing model may pile in and fight as normal, with the following exceptions:

• Units that charged this turn fight first, per the 40k Fight Phase rules. This applies to both 40k and AoS units, so if three units of Liberators charged this turn, they would all get to attack before their 40k opponent would retaliate.
• Both 40k and AoS Units may consolidate per the 40k rules after attacking.

Attacking

Attacks

AoS Attacks

When an AoS unit targets a 40k unit, use the AoS attack sequence as normal from page 6 of the AoS Core Rules.

40k Attacks

When a 40k unit targets an AoS unit, use the normal attack sequence from the 40k core rules, with the following exceptions:

To-Wound

Instead of using the Wound Roll chart from the 40k Core Rules, use following chart to determine what the required To-Wound roll is:

S	To-Wound
1	6+
2	5+
3	4+
4	3+
5-9	2+
10+	2+, re-roll failed wounds

Furthermore, when 40k weapons target AoS units, weapons with a Strength higher than 5 gains a bonus to its AP value as follows:

S	AP bonus
6-9	-1
10+	-2

For example, a Lascannon, normally S9 and AP -3 has a To-Wound roll of 2+ and has a Rend of -5.

Rend vs. AP

An AoS Weapon’s Rend and a 40k Weapon’s Armour Penetration (AP) value are synonymous:

• AoS Rend reduces a 40k model’s Armour Save by the designated value
• 40k AP reduces an AoS model’s Save by the designated value

Damage

• AoS Damage carries over as normal; 40k damage does not (again, as normal)
  • For example: A Freeguild Steam Tank targets an Astra Militarum Infantry Squad with its Steam Cannon. Its controlling player hits and wounds as normal, and rolls 4 for its damage roll. It therefore kills four members of the infantry squad. Conversely, if a Space Marine Predator hits and wounds a unit of Freeguild Handgunners with a single lascannon sponson, it will only ever be able to inflict a single (albeit rather horrible) casualty.

Characters and Heroes

Instead of the rules for targeting Characters and Heroes in 40k and AoS, respectively, use the following:

Some models are noted as being a CHARACTER in 40k or HERO in AoS on their datasheet or warscroll. These heroes, officers, prophets, and warlords are powerful individuals that can have a great impact on the course of a battle. The swirling maelstrom of the battlefield can make it difficult to pick out such individuals as targets, however. A 40k CHARACTER or AoS HERO can only be chosen as a target in the Shooting phase if they are the closest visible enemy unit to the model that is shooting. This does not apply to CHARACTERS or HEROES with a Wounds characteristic of 10 or more, due to their sheer size.

Army Composition

Points values or Power Level

If both players wish to use points to roughly balance their forces, AoS units pay half their usual points when playing against a 40k army. Therefore, a 1000-point 40k army would fight a 2000-point AoS army, and so on.

Scenarios

You may use any scenario from Warhammer 40,000 or Warhammer Age of Sigmar that you like. The rules for various AoS Realms in particular give a great starting point, as many of them have mechanisms limiting shooting, etc.