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Forbidden Power: Rules Rundown (Mercenaries, New Allegiances etc)

What is Forbidden Power?

Forbidden Power is the newest supplement for Age of Sigmar, continuing the Soul Wars storyline.

Besides some more story, endless spells and a terrain feature we also get new rules for the game (matched play and narrative stuff).

In this article, I will go through the rules trying to dispell all the confusion regarding new Allegiances, Mercenaries, the Campaign, The Penumbral Engine and everything else the Forbidden Power has to offer in terms of new stuff.

While I go into a lot of details, you will need to buy the book to use the rules.

This rundown is only to make sure you know whether or not this is a good purchase for you and your gaming group.

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A note on the artwork

In this article, I have used some of the amazing artwork from the Forbidden Power book. I have done this to convey the right aesthetic and feel of the expansion. All rights for the images are reserved by Games Workshop and the very talented artists that have made them (and I hope they will not get pissed by me displaying the artwork here).

Forbidden Power: Content Overview

In the Soul Wars: Forbidden Power box you will get the following stuff:

  • 4 Endless Spells (useable by all factions).
  • 1 Penumbral Engine (non-faction specific terrain piece).
  • Warscroll Cards for the 4 Endless Spells, the Penumbral Engine and for the Terrain Pieces released alongside Forbidden Power (but not part of this box itself).
  • Some tokens for the campaign.
  • 88-page book (most of it is lore but it also covers new allegiances, new rules for mercenaries, the Penumbral Engine, new Campaign and so on).

In this article, I will only focus on the new rules covered in the book.

The Content of the Age of Sigmar expansion Soul Wars: Forbidden Power

Is the New Rules In Forbidden Power part of Matched Play?

A bit surprising, but yes! People that went to Warhammer Fest (where Forbidden Power was revealed fully) say that GW confirmed that the different extra rules were meant to be part of the matched play system.

To back this up, the Endless Spells and the new terrain feature has pitched battle profiles at the end of the book and we know that more Mercenary Companies are coming in the next Generals Handbook.

This continues GW’s trend from Malign Sorcery, making it a good bet that whatever they cook up in the upcoming instalments, they actually have Matched Play in mind as well as open and narrative.

Remember: you can still elect to play without mercs or whatever you don’t like, but they are officially part of Matched Play.

Unsure of what Matched Play is? My article here will get you up to speed if you are new to the game.

Nagash and Sigmar merging together in a nice portrait (or selfie?)

The Rules for Fighting in the Region Stygxx (part of the Realm of Death)

We get some rules covering fighting in a specific sub-section of the Realm of Death, Stygxx.

The realm is primarily designed to be used in the campaign found in the book, but you can use it any games you like.

Stygxx follows the normal rules for fighting in a realm. 

The Stygxx region features the following effects:

  1. A -2 bravery debuff spell.
  2. A command ability that can give +1 attack characteristic to a unit.
  3. A command ability that lets you sacrifice wounds from a unit to heal your heroes.
  4. Units with the keyword “Priests” gain a prayer. The prayer has a low chance of giving you 1 extra command point.
  5. The realmscape feature of Stygxx is that any spells where you roll a double is automatically cast successfully AND your opponent cannot attempt to unbind it.

All in all some pretty cool realm things and quite powerful.

Playing in Stygxx is certainly not going to be boring.

What are the Rules for the new Allegiance “Lethisian Army” (New Order Allegiance)

Something new introduced in Forbidden Power is two new Allegiances, one for Order and one for Death.

You can select to have the “Lethisian Allegiance” instead of a normal Allegiance (say Stormcast Eternals or Order Allegiance).

If you do so units in your army gain the “Lethisian Defender” keyword and you gain access to the Lethisian Allegiance abilities.

You can only have units with the following keywords if you want to pick this allegiance:

  • Stormcast Eternals
  • Idoneth Deepkin
  • Kharadron Overlords
  • Fyreslayers
  • Excelsior Warpriest

In addition to those restrictions the army cannot include any units with the following keywords:

  • Hammers of Sigmar
  • Vostarg
  • Volturnos

So that basically boils down to no named heroes, but any mix of Stormcast, Sea-elves, Flying-Dwarfs, Burning-Dwarfs and the weird priest guy. That is pretty cool!

If you are in doubt regarding how Allegiance Abilities work in general (army special rules) you can read my guide on it here.

So what do you get if you pick this allegiance instead of being mixed order?

  1. 3 (or 5 depending on how you count) Battle Traits
  2. 3 different Command Traits
  3. 3 different Artefacts
  4. 3 different Prayers
A stormcast eternal. She is really banged up trying to hold those Stormvaults for Sigmar.

The Battle Traits (army wide buffs) for the Lethisian Army:

  1. You can re-roll battleshock for your units.
  2. Your Human and Duardin units that are charged gain+1 on hit rolls against the charging units.
  3. +1 on move characteristic for the Idoneth Deepkin units
  4. +1 on charge rolls for the Idoneth Deepkin units
  5. Command Ability: use at the start of the combat phase. Pick a Liberator unit wholly within a Stormcast Eternals hero. The Liberators cannot pile-in in that phase, but they gain +1 on saves in that combat.

3 Command Traits (you can pick 1 trait for your General):

  1. Raven Priest: The general gains the Priest keyword (so it can take 1 prayer from the army prayer list). If the general is already a priest, he can select two prayers from the list instead.
  2. Solemn Soul: Units wholly within 12″ of the general do not have to take battleshock tests.
  3. Sinister Aura: +1 on the general’s wounds. Subtract 1 from Bravery of enemies within 6″

3 Artefacts:

  1. Crown of Raven Feathers: +5 negate allocated wounds
  2. Silvered Blade: +1 on the damage of one of the bearers weapon. If you target a Death unit you add +2 damage instead.
  3. Flask of Lethisian Darkwater: One use per battle, used at the start of the combat phase. Heal d6 wounds.

3 Prayers (priest only, kind of like spells but cannot be unbound)

All are cast on a +3 (on a single dice).

  1. Morrda’s Resurrection: return d3 in wound worth of slain models on a unit within 18″.
  2. Morrda’s Eye: enemy unit within 18″ get minus 1 on hit rolls until the start of your next hero phase.
  3. Morrda’s Embrace: works on all friendly units wholly within 12″. Reroll save rolls of 1 until the start of your next hero phase.

Overall Verdict on the Lethisian Allegiance:

  • Thematically it is very awesome and fits great with the story in the book.
  • Mixed Allegiances like this bodes well for the future. What kind of mixed Destruction and Chaos Allegiances will we see in the future?
  • You get a lot of cool models to pick from!
  • The Battle Traits are okay. +1 move and charge on the Aelves is very nice, but in general, the buffs are very defence oriented. I can see a cool themed “last stand” defender army formed on the backbone of these abilities.
  • The artefacts are somewhat weak (you could probably get some better ones via Malign Sorcery)
  • The Prayers are quite good. Good chance to cast and no way for your opponent to do anything about them. Getting access to two on your general via the command trait is not a bad option
  • Does the allegiance hold enough power to be competitive? Unlikely, with the lack of battalions and not enough really “good” powers. Is it a bad thing? No, it is probably best that armies like this are more casually oriented and not sudden “top tier” armies.
Stormcast trying to turn back the tide of the nighthaunt

What are the Rules For the Legion of Grief (New Death Allegiance)?

You can select to have the “Legion of Grief Allegiance” instead of a normal Allegiance (say Nighthaunt or Death Allegiance). If you do so units in your army gain the “Legion of Grief” keyword.

You can only have units with the following keywords in the army:

  • Deadwalkers
  • Deathlords
  • Deathmages
  • Deathrattle
  • Nighthaunt

In addition, if you want to take any Mortarchs, you must also include Lady Olynder and she must be the general.

So that basically boils down to zombies, super big undead dudes, necromancer guys, skeletons and ghostly people. Sweet!

So what do you get if you pick this allegiance instead of being mixed Death?

  1. 5 Battle Traits
  2. 3 different Command Traits
  3. 3 different Artefacts
  4. 3 different Spells

The Battle Traits (army wide buffs) for the Legion of Grief:

  1. 4 Grave Sites (like the Legions of Nagash rule). You can “summon” your units from the grave sites instead of setting them up as normal and they are used in some of the special abilities below.
  2. In each of your hero phases, you can heal d3 wounds or return models up to d3 wounds on one unit within 9″ of a gravesite.
  3. Your units within 6″ of one of your Legion of Grief heroes get a +6 shrug save.
  4. Enemy units within 6″ of your units gain -1 bravery.
  5. Command ability, use at the end of your movement phase. Pick a gravesite within 9″ of the general. You can return one Legion of Grief unit that has been destroyed and place it wholly within 9″ of the gravesite.

3 Command Traits (you can pick 1 trait for your General):

  1. Amethyst Glow: Your general becomes a wizard (cast one spell and unbind one spell). If he is already a wizard, he instead knows two spells from the Legion of Grief spell list.
  2. Vassal of the Craven King: as long as the general is on the battlefield, you get your command points back after use on a +5.
  3. Tragic Emanations: Enemy units within 12″ of the general gets -2 bravery.

3 Artefacts:

  1. Grave-sand Gem: each hero phase you can pick between dealing 1 mortal wound to a unit within 6″ or heal 1 wound on the bearer.
  2. Gothizzari Mortayry Candle: Missile weapons get -1 on hit rolls against the bearer.
  3. Souldrain Pendant: Roll a dice for each enemy unit within 3″ of the bearer at the end of the combat phase. On a 4+ you deal 1 mortal wound to the unit.

3 Spells (each wizard in the legion of Grief knows one of them)

  1. Dread Withering: cast 5, debuff enemy unit within 18″. Until your next hero phase that units get -1 on saving rolls.
  2. Wail of Doom: cast 8. Roll a dice for each enemy unit within 6″. 4+ you deal d3 mortal wounds to it.
  3. Shroud of Terror: cast 8, debuff a unit within 12″ until your next hero phase. that unit gets minus d3 bravery.

Overall Verdict on the Legion of Grief Allegiance:

  • Summoning back a complete unit can be really powerful.
  • The spells seems very good. You can do some crazy amount of minus bravery stacking.
  • The models you get access to are cool, but some of them serve the exact same purpose.
  • Would you be better of just doing a Legions of Nagash army instead?

Get your own copy of Forbidden Power

The old Dogs of War armybook for the Oldhammer Warhammer: Fantasy

How do the new rules for Mercenaries Work?

The Mercenary system is a new mechanic, that continues on the building block of the Ally System (if you are in doubt on how allies work, you can read my article on it here).

While not totally Dogs of War (my favourite thing in Oldhammer), we got something a bit similar.

In Forbidden Power, two different “Mercenary Companies” is available for hire (with more companies confirmed to come in the next Generals Handbook).

The General Rules for Mercenaries are as follows:

  1. Any army, regardless of allegiance, can hire in any of the Mercenary Companies. Think of it in terms of special allies that any army can hire.
  2. If you take a Mercenary company they will use up the same pool of points you have for allies.
  3. Just like with allies, only 1 out of every 4 unit can be an ally or mercenary. Again, exactly like allies and work in conjunction with the rules for allies.
  4. Units you hire from the Mercenary Company all gain the “Mercenary” keyword in addition to the normal keywords they have.
  5. Just like Allies, the Mercenary Company cannot gain any benefits from Allegiance abilities and a Mercenary hero cannot be the general.
  6. Just like Allies, the Mercenary Company does not count towards the minimum number of battleline units, but they do count towards the maximum amount of leaders and behemoths.
  7. When you deploy them they count as having the same keywords as your allegiance. From that point onwards they do not count as having that keyword.
  8. If you have a Mercenary Company in your army, you will not generate a command point in your first turn (for the turn after and beyond you generate one command point as normal each turn).
  9. You cannot include a named character in your Mercenary Company.
  10. You can only have one Mercenary Company in your army.
  11. If units from your Mercenary Company summons any dudes, they will also have the Mercenary keyword (but in battle, you can go above the normal threshold of 1-4 units).
A pretty slick symbol thingy in Soul Wars: Forbidden Power book

What Mercenary Companies are in Forbidden Power and What Special Rules do They Get?

In the Forbidden Power book, you get two different Mercenary Companies.

The Greyfyrd Lodge (Fyreslayers) and the Tenebrous Court (Flesh-Eater Courts).


Greyfyrd Lodge Mercenaries (Fyreslayers)

  1. If you pick this as the Mercenary Company for your army, you can include any Fyreslayers unit with the exception of units with the “Auric Runefathers” keyword.
  2. As per the rules of Mercenaries, all of the units you include in that way get the Mercenary keyword.
  3. The Fyreslayers Mercenaries can add +1 on hit rolls for melee weapons against units that charged that same turn (so an offensive buff when you get charged).
  4. From the third battle round and onwards you must subtract 1 from bravery from Fyreslayers Mercenaries unless they are wholly within 18″ of your general (so the mercs are more likely to run away if they cannot see the dude who is paying them their moneyz).

Tenebrous Court Mercenaries (Flesh-Eater Courts)

  1. If you pick this as the Mercenary Company for your army, you can include any Flesh-Eater Courts unit with the exception of unit Royal Terrorgheists and Royal Zombie Dragons. Note that it is those two specific units you cannot bring (so as an example the Ghoul King on Royal Terrorgheist is fair game but the Royal Terrorgheist on its own is not ok to bring).
  2. As per the rules of Mercenaries, all of the units you include in that way get the Mercenary keyword.
  3. You can add +1 on hit rolls for Flesh-Eater Courts Mercenaries if they made a charge move in that same turn.
  4. Your Flesh-Eater Courts Mercenaries can never make retreat moves (the boys gotta eat!)
The four new warscroll cards for the four new endless spells in Soul Wars: Forbidden Power

How does the Rules Work for the Endless Spells in Forbidden Power?

The general rules for the endless work exactly the same as normal endless spells.

It does not require any specific faction or keywords to cast them, so they are open to all armies that have a wizard. If you are in doubt how the general rules for endless spells work, I have written a bit on the subject here.

You get a printed version of the warscrolls in the box, but you can also find them in the AoS App as well as on GW’s website with the product (just like normal warscrolls).

  • Soulscream Bridge: 80 points
  • Shards of Valagharr: 40 points
  • Lauchon the Soulseeker: 60 points
  • Horrorghast: 60 points

Are there any Artefacts in Forbidden Power?

Yes and no. The artefacts, unlike the artefacts in the Malign Sorcery expansion, are restricted to be used in the Campaign found in Forbidden Power.

You could decide to use them in your narrative or open games, but for matched play purposes they do not exist.

The Artefacts in this expansion grows in power the further you get in the campaign. It is pretty cool!

Nighthaunt fighting Skaven in Age of Sigmar

How does the Campaign in Forbidden Power work?

In Forbidden Power you get the rules for running the campaign “Stormvault”. The campaign is based upon the lore and narrative in the book. Sigmar’s secret Stormvaults are no longer hidden after the Necroquake.

The Stormvaults contain powerful weapons, so every General and his mom is finding the next available realm portal to get their hands on some shinies (while Sigmar is scrambling to defend them). 

The rules for the Stormvault campaign are quite extensive, but here is what you need to know before you decide to buy it:

  1. There are no restrictions on the number of players you can have in the campaign (I heard a rumour that it was only for 4 people, so I was a little worried about that).
  2. They suggest playing once a week, but you can run it as you want.
  3. You can weave your own specific narrative about the campaign. The gist of the campaign is the battle for different Stormvaults, but those can be located in multiple different realms (making sure you can use all of those weird and lovely rules for fighting in different realms).
  4. At the start of the second game, each player gets to select one of 6 “Awakened Artefacts”. There are some very hot and powerful ones and they each have a chance to grow in power after each battle (dependent on whether or not you are able to complete the “artefact goal”). Each artefact has 5 power levels.
  5. Your Allegiance and your General must be the same throughout the campaign. The hero that gets the artefact must also be the same throughout the campaign. Everything else you are free to change out.
  6. The campaign stipulates nothing about points, so you will have to decide in your group how you do it. Doing an escalation type league would be very appropriate (start at low points, but slowly raise the level of points allowed each week).
  7. In the campaign, you get four pitched battle plans and four “narrative battleplans” (battleplans where the goals are asynchronous).
  8. When you win a minor or major victory you have captured a Stormvault and gain a reward. There are 6 rewards and you can never get the benefit of the same one twice. Two are for the rest of the campaign (+1 level on the artefact and +1 wound on your general). The four remaining is the ability to bring one of the four new endless spells for free in the next battle and auto-cast it once without your opponent being able to unbind it.
  9. When someone has won 6 Stormvaults, the campaign moves into the last game. This has to be played with the Battleplan: Grand Stormvault and whoever wins that game wins the campaign. Only the four players with the most Stormvaults (wins) participate in the last battle. The tiebreaker is the highest level of artefact.
  10. You get some Tokens in the box and campaign roster in the book to run the campaign more smoothly. 

Get your own copy of Forbidden Power

New Soul Wars: Forbidden Power Penumbral Engine

Can any Faction take the new Terrain Piece Penumbral Engine and what does it do?

Yes, an army with any allegiance can take it. If you want to take it in matched it will cost you 100 points AND these will be deducted from the points you can take allies with.

Now 100 points are quite a lot of points but the effect can be really good. The biggest downside is the randomness of the engine.

You plop down the engine in your territory, 12″ from enemy territory and at least 1″ away from other terrain features.

At the start of the first battle round roll a d6 and consult the chart.

All Penumbral Engines on the battlefield gain the same effect. At the start of each subsequent battle round, you roll a d6. On 1-4 the effect stays the same. If you roll 5-6 you will need to roll on the chart again for a new effect.

Effects of the Penumbral Engine:

  • 1-3 Re-roll save rolls of 1 for units wholly within 12″ of the engine (it seems to be all units, also the enemy).
  • 4-6 If you have a hero within 12″ of the engine, you gain one extra command point at the start of your hero phase.

Command points are okay, but you might as well buy 2 for 100 points and call it a day. The real power is in the Mystic Shield save bubble , but will it be worth the points when it is random?

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