Detachment Focus: Pactbound Zealots (Updated January 13, 2025)

In this series of articles we take a deep dive into a specific detachment for a faction, covering the faction’s rules and upgrades and talking about how to build around that faction for competitive play. In this article, we’re covering the Pactbound Zealots Detachment for the Chaos Space Marines.

The Tenth Edition release of Codex: Chaos Space Marines gives the faction access to a whopping eight detachments, each with their own strengths and weaknesses. These can dramatically change how the army plays, as each one tends to push players to build in a different way. In this series we’re diving deep into each Detachment and talking about what its rules are and how to play it.

Changelog

• Update: 2025-01-13 for the Q4 Dataslates and a new list
• Update: 2024-07-30 for the Q2 Balance updates and new lists
• Published: 2024-05-11

Detachment Overview

Pactbound Zealots is both the revised version of the Index Detachment – Slaves to Darkness – and the Word Bearers Detachment for Chaos Space Marines. Rules-wise, it retains its core identity from the Index, albeit with a few changes, some of which are bigger than others. It’s still about giving your units mark-specific bonuses which improve their offensive output, and the Stratagems on offer are extremely solid. Pactbound Zealots may often be overshadowed a bit by newer, flashier Detachments like the Renegade Raiders and Soulforged Warpack, but it’s still one of the game’s strongest Detachments.

Detachment Rule: Marks of Chaos

When mustering your army, when you select a HERETIC ASTARTES unit to include in your army, if that unit is not an EPIC HERO and does not already have one of the following keywords, you must select one for that unit and note it on your Army Roster: KHORNE, TZEENTCH, NURGLE, SLAANESH, CHAOS UNDIVIDED. Each time a unit with one of these keywords gains a weapon ability as a result of a Dark Pact and does not fail the resulting Leadership test, until the end of the phase, that unit gets the associated ability below:

• Chaos Undivided – Each time a model in this unit makes an attack, re-roll a Hit roll of 1.
• Khorne – In the Fight phase, if this unit’s weapons gained the [LETHAL HITS] ability as the result of a Dark Pact, each time a model in this unit makes an attack, an unmodified Hit Roll of 5+ scores a Critical Hit.
• Nurgle – In the Shooting phase, if this unit’s weapons gained the [SUSTAINED HITS 1] ability as the result of a Dark Pact, each time a model in this unit makes an attack, an unmodified Hit Roll of 5+ scores a Critical Hit.
• Slaanesh – In the Fight phase, if this unit’s weapons gained the [SUSTAINED HITS 1] ability as the result of a Dark Pact, each time a model in this unit makes an attack, an unmodified Hit Roll of 5+ scores a Critical Hit.
• Tzeentch – In the Shooting phase, if this unit’s weapons gained the [LETHAL HITS] ability as the result of a Dark Pact, each time a model in this unit makes an attack, an unmodified Hit Roll of 5+ scores a Critical Hit.

There are two restrictions here: First, you can’t give the KHORNE keyword to a PSYKER unit, and second, a CHARACTER can only be attached to a unit if both units share the same keyword from the above list.

There are two changes here from the Index Detachment. The first and biggest being that you now have to pass your Leadership test for the Dark Pact in order to score the bonus. Combined with taking your test before shooting, this makes the Pact a bit less onerous, while also making icons more valuable. Second, there’s no longer a restriction on transports, though this may be reinstated with the next dataslate. Note as well that Abaddon no longer has all five marks, and so there isn’t a way to get multiple benefits at the same time without a Helbrute around.

Even with these changes, this is still one of the strongest Detachment rules in the game. Popping off Critical Hits on a 5+ to get extra hits or Lethal hits is huge, giving the entire army a massive boost of offensive output. Even with the risk of taking wounds before attacking, you’re going to basically be doing a pact every time a unit shoots or fights, and you’ll want to actively plan your marks around what works best on a unit. Generally speaking, Nurgle, Slaanesh, and Undivided are the best here, in part because Sustained Hits is better than Lethal Hits in most cases, and in part because the stratagems keying off those marks are just much better.

Most of the time those decisions will be pretty easy, however:

• If your unit’s primary role is shooting, or it’s just not great in melee (or not intended for melee), you likely want to give it either the Nurgle or Chaos Undivided keyword. Nurgle gives you a big output boost on units like Land Raiders and Obliterators, and is great on transports and units which don’t want to be hit thanks to the Dark Obscuration Stratagem. Chaos Undivided is also solid, since being able to get full re-rolls to wound with Profane Zeal can make it easier to fish for Devastating wounds on things like combi-weapons and the Forgefiend’s guns.
• If your unit’s primary role is fighting in melee, then you’re likely considering either the Slaanesh or Chaos Undivided keywords. Slaanesh is a better pick for faster units like Possessed – the Torpefying Refrain Stratagem lets a Slaanesh unit Advance and Charge. That’s wasted on Chosen, but on Possessed who move 9″, it’s a huge boost. Khorne is also an option, though generally Lethal Hits is only okay and fighting on Death on a 3+ isn’t particularly exciting, especially since you can’t use Pacts when you do that fight. There’s some value in using a Master of Executions for this, since you can use his re-roll hits ability against units below starting strength to fish for Lethals on a 5+ and punch up against big threats.
• For all-rounder units which can do both, the mark of Chaos Undivided is usually the play. Chosen and Chaos Terminators do well with these. We also haven’t talked as much about the Mark of Tzeentch; generally you want Sustained Hits over Lethal hits on your shooting because you’ll seldom be attacking with a massive volume of bolter shots and Lethal Hits doesn’t combo with devastating wounds on things like your Forgefiend and combi-weapons. The Skinshift Stratagem gives Tzeentch units the ability to regenerate a destroyed model, which can provide some big value. It’ll give you the best value on Terminators and Obliterators (though Obliterators are much better off with Nurgle or Undivided).

Current successful meta lists tend to mix marks across a large number of units (typically Nurgle and Undivided, with some Slaanesh), choosing the most appropriate tool for each. Lists will also split marks where it doesn’t make sense to double up. Note that if you’re taking a Helbrute, their ability triggering both effects for your Dark Pact means that you’ll get both effects on a 5+, since the Detachment rule makes unmodified rolls of a 5+ critical hits, and that’s all those effects are checking for.

Enhancements

• Talisman of Burning Blood (15 points) – Khorne model only. Add 1 to the Attacks and Strength characteristics of the bearer’s melee weapons. Each time the unit makes a Dark Pact and does not fail the Leadership test, they get +D3 to each of those instead. This is cute, but there’s no real reason for you to take a Khorne character. The Master of Executions is probably the best target for this, but it’s not bad on a Daemon Prince, either. +D3 strength isn’t as good as +D3 damage, but it’s interesting to think about how this might stack with Eye of the Gods to create some horrifying late-game monsters.
• Eye of Tzeentch (15 points) – Tzeentch model only. Each time the bearer’s unit makes a Dark Pact and does not fail the Leadership test, if you rolled an 8 or more on that test, you get 1 CP. This is a little worse than it used to be – your odds drop from about 52% to 41% – but it’s also 25 points cheaper, which is a fair tradeoff. That said, this still requires you take the Mark of Tzeentch, and I’m not sure that’s worth it on top of the points. You won’t need this if you’re taking Abaddon, notably, as he has a better version built in.
• Orbs of Unlife (15 points) – Nurgle model only. At the end of each Fight phase, roll one D6 for every enemy unit within 6″ of the bearer, adding 1 if the bearer’s unit made a Dark Pact that phase and did not fail the Leadership Test. On a 4+, that enemy unit suffers D3 mortal wounds. This is a cute little way to turn your character into a Death Guard Chaos Lord, and those are pretty solid. That said, your infantry unit characters don’t always have the Mark of Nurgle, though this could be OK on a Dark Commune, and there the Icon will help you easily mitigate any downside to needing to pass the test to get the effect.
• Intoxicating Elixir (15 points) – Slaanesh model only. The bearer gets the Feel No Pain 5+ ability. Each time the bearer fights if their unit made a Dark Pact this phase and did not fail the Leadership test, then after the bearer finishes their attacks one enemy unit hit by them has to take a Battle-shock test. The Battle-shock test is whatever but the 5+ FNP is basically the equivalent to giving your character 50% more wounds. If you’re taking a Daemon Prince with the Mark of Slaanesh and have 15 extra points, slam this on them to improve their longevity.

Stratagems

The six Stratagems on offer in the detachment tend to be pretty specific and aimed toward a single mark, but what’s available is an absolutely bonkers from a power level standpoint. Profane Zeal and Dark Obscuration are two of the game’s best Stratagems despite nerfs, and if they were the only ones you had access to Chaos Space Marines would still be a top-tier army. All of these are priced at 1 CP, which means they’re all free when you use the Chaos Lord’s ability to reduce their cost by 1.

• Eye of the Gods (Epic Deed, 1 CP) – Use in the Fight Phase, just after one of your non-DAMNED, non-DAEMON, non-EPIC HERO CHARACTER units kills an enemy unit. Pick a CHARACTER model in that unit and until the end of the battle it gets +1 to its Move, Toughness, and Wounds characteristics, plus +1 to the Attacks, Strength, and Damage of its melee weapons. This is a cute upgrade, but not something you’ll really need most of the time. If you can snag an early melee kill with a Chaos Lord it can be pretty solid, giving you a 3-damage hammer for doing Devastating Wounds and keeping the party going after you’ve already popped his once-per-game ability to hulk out. If you haven’t already spent your free Stratagem on Profane Zeal or Torpefying Refrain, this is a solid time to pop it.
• Profane Zeal (Battle Tactic, 1 CP) – Use in your Shooting or Fight phase on a unit which hasn’t fought or shot yet. Until the end of the phase. If the unit is Chaos Undivided, it can re-roll all wound rolls until the end of the phase. This keeps the changes from the Q1 dataslate and even with that nerf it’s still incredibly, wonderfully good. While it no longer gives you full re-rolls to hit, you still get re-roll 1s to hit from your Dark Pact with the Undivided unit and the real value here is being able to fish for Devastating Wounds. This is fantastic on Chosen, Terminators, Obliterators, Vindicators, Possessed, Land Raiders, Predators, and Forgefiends. It’s a fantastic Stratagem to pop with your Chaos Lord’s Lord of Chaos ability.
• Eternal Hate (Strategic Ploy, 1 CP) – Use in the Fight phase after an enemy unit picks its targets and pick a unit they targeted. Until the end of the phase each time a model in that unit is destroyed, roll one D6 and add 1 to the result if the unit is a Khorne unit. On a 4+, the model can fight after the attacking model’s unit has finished making its attacks, then it’s removed from play. This is a good way of making your opponent regret charging a key unit, stabbing back at them with some nasty hits before you go. Note that as models fight here and not the unit, you cannot perform a Dark Pact when a model fights on death (you only pact when you select a unit, not a model – see our Ruleshammer on Pacts for more on this).
• Skinshift (Epic Deed, 1 CP) – Use in your Command phase and pick a unit. A model in that unit regains 3 lost wounds. If that unit is a Tzeentch unit below Starting Strength, it can return a dead model (excluding character models) with full wounds remaining. This is best when it’s bringing back expensive models, so Obliterators and Terminators. Obliterators are better served with other marks however, so you may get more value out of using this to heal a vehicle which has taken damage. In those cases it’s useful for shaking off negative modifiers from a low wound total or going above half wounds so you don’t have to do a Battle-shock test. It’s also not terrible on a unit of Accursed Cultists, since they can’t regenerate any more.
• Torpefying Refrain (Strategic Ploy, 1 CP) – Use in your Movement phase and pick a unit. Until the end of your turn, that unit can shoot and charge even if it Fell Back. If that unit is a Slaanesh unit it, can also shoot and charge even if it Advanced. This is a very solid, very versatile Stratagem. It’s good on Legionary units for turning them into baby Chosen, with more versatility for doing actions and getting into combat, and great when it’s free thanks to their attached Chaos Lord. It’s also great on quick, pure melee units that want to get into combat quickly and which don’t really have shooting attacks – so the Possessed, Daemon Prince, Warp Talons, and Maulerfiend are all options here. It’s also great for taking your tanks out of melee and still shooting with them without suffering the penalty from Big Guns Never Tire, and it’s fantastic on Obliterators, who don’t have that ability at all. It may not come up in most games, as you’ll already likely be strapped for CP with the other excellent stratagem choices available, but it can be a nasty surprise in a pinch. On an unrelated note, the new name for this Stratagem makes no sense.
• Dark Obscuration (Strategic Ploy, 1 CP) – Use in your opponent’s shooting phase just after they pick targets, and pick one of those targets. Until the end of the phase, your unit gains the Stealth ability. Also, if the unit is a Nurgle unit, until the end of the phase it can’t be selected as the target of a ranged attack if attacking model is more than 18″ away. The other half of the one-two punch with Profane Zeal, and a purely defensive tool, so it never really interferes with Zeal. This isn’t necessarily why you take the Mark of Nurgle on your shooting units, but it’s a great bonus since it can keep them safe. If you’re taking a Cultist Mob for holding your backfield objective, you’ll want to mark them Nurgle just so they can use this, as it prevents situations where you might lose them on turn 1 to indirect fire before they have a chance to sticky your home objective.

Playing This Detachment

The strategy here really hasn’t changed since this was Slaves to Darkness. The general idea here is to pick the marks that best benefit each unit in your army and just always unload with a Dark Pact unless doing so would otherwise be too dangerous. You’ll often find yourself firing off Obscuration in the first couple of rounds in your opponent’s turn, and a Profane Zeal or two in your turn. The good news about Pact bonuses based on marks is that they don’t require a ton of additional strategy; you’ll almost certainly be simplifying your choices by picking the thing your mark gives you a bonus for, and that means fewer choices, generally. With this Detachment you want to focus on units which can take an icon where possible, as the ability to re-roll your failed Leadership tests is very important, both in terms of keeping them alive and securing your Detachment marks bonus. On that note, the following units get icons or re-rolls to leadership tests:

• Legionaries
• Chaos Bikers
• Chosen
• Cultist Firebrand (gives his unit re-rolls)
• Dark Apostle (doesn’t give re-rolls but improves Ld to 5+)
• Possessed

When it comes to building this army, you want a mix of everything. Your non-Chosen melee units generally want the mark of Slaanesh so they can Advance and Charge, your Chosen typically want the mark of Chaos Undivided to do more damage, your Possessed will want either Slaanesh (advance + charge) or more likely, Undivided (full re-rolls to wound to fish for dev wounds). Your vehicles take the Mark of Nurgle or Undivided, depending on how you want to use them – high shot count weapons like the Predator Destructor and Vindicator want Nurgle, while the Land Raider usually wants Undivided. And you want to give your backfield Cultists the mark of Nurgle. Khorne and Tzeentch don’t get much play, unless you’re going for a specific unit strategy. Even then, regenerating with Tzeentch isn’t as good as not getting shot with Nurgle or just being in combat sooner.

Strengths

• Insanely good damage output thanks to an even better version of Dark Pacts. A Chaos Vindicator throwing out Sustained Hits on a 5+ is just insane to see, and with a Helbrute supporting it you can do some very nasty things.
• Some of the best Stratagems in the game – Everything you need is here, from untargetability to full re-rolls to wound to advance and charge.
• Versatility – almost any unit in the Codex can benefit from this rule in some way or another, giving you a lot of options for building.

Weaknesses

• Stratagems being locked to marks means that while you have some of the game’s best, units can only really benefit from the full effects of one of them, so you’ll have to make some choices around what Stratagems you want to have access to before the game.
• Bad internal balance around marks – Khorne and Tzeentch just don’t rate, both in terms of Lethal Hits being less valuable but also their Stratagems just aren’t nearly as good.
• Only getting your Detachment benefit when you pass a Dark Pact is really rough, and even with re-rolls you’re going to fail at least a couple of times per game, and it’s always going to cost you more than you’d expect.

A Sample List

Although they’re not as flashy or popular as some other Detachment options, there’s still plenty of juice in the Pactbound Zealots detachment. Brian Crothers took this list to a 3-1-1, 5th place finish at the Grand Clash GT in Ontario in mid January. It’s a more melee-focused list with plenty of tricks up its sleeve.

Brian's List - click to expand

This list runs heavy on melee threats – you’ve got Chosen, Legionaries, and Possessed – oh my. The Nemesis Claw are an important piece here, able to make charges with other units and turn off Stratagems, preventing them from interrupting when you have multiple combats queued up at once. The list carries the mark of Slaanesh on the Claw and its Legionary units to give them advance and charge, while it keeps Undivided on its Chosen and Possessed to maximize their damage output and give them access to Profane Zeal. Bile joins one unit of Chosen (He has the UNDIVIDED keyword) while the Dark Apostle joins another and the two Chaos Lords hang out with Legionaries. The Master of Executions meanwhile becomes the second character attached to a unit of Chosen, and they’re the unit that’s going to walk, since they’re sitting on 14 models while Bile and his unit are only 12 when you count his assistant goober. This is one of the most annoying parts of Pactbound Zealots – while it’s easy to suss out who goes where from a list based on marks for the units, characters, and transports, you’re also very limited in how you use everything.

Final Thoughts

This is just a very good Detachment; it makes all of your units better in ways that are helpful to them and also gives you some very good Stratagems to work with. Slaves to Darkness was a major part of why Chaos Space Marines were among the game’s best factions and Pactbound Zealots carries that on. It’s a super fun and flavorful way to build the army and play, and does a great job of giving us a Word Bearers Detachment worth playing.

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