Detachment Focus: Fellhammer Siege-Host (Updated December 19, 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 Fellhammer Siege-Host Detachment for the Chaos Space Marines.

The Tenth Edition release of Codex: Chaos Space Marines gave 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. This article will be focusing on the Fellhammer Siege-Host Detachment.

Changelog

December 19, 2025: Updated with a new list
January 9, 2025: Updated with errata, dataslate changes, and a new list
May 11, 2024: Initial Publication

Detachment Overview

It’s pretty clear from the art and the rule names that the Fellhammer Siege-Host is intended to represent the Iron Warriors on the tabletop, with their siege-and-trench warfare style of combat and their philosophy of “Iron Within, Iron Without.” As a result the Siege-Host offers some decent durability buffs over other Chaos Space Marines Detachments, though it’s not as vehicle-focused as you might expect. Instead the Stratagem focus here is on heavier infantry, with support for short-ranged shooting and skirmishing that benefits the likes of Terminators and cult troops.

Detachment Rule: Iron Fortitude

Each time a ranged attack targets a non-DAMNED HERETIC ASTARTES unit from your army, if the Strength of that attack is greater than the unit’s Toughness, subtract 1 from the Wound roll.

This is alright. It’s a solid defensive buff that’s both good on your vehicles for ensuring that really big guns like Lascannons and Railguns only wound them on a 4+, and it’s great for making sure your Infantry aren’t going down easy to the likes of plasma guns and mortars. The big downside here is that it does nothing for you in melee, suggesting that Fellhammer Siege-Host armies want to scrap at a distance with opponents, or at the very least if they engage in melee they want it to be on their terms. That's a problem given the Stratagems in the Detachment, and the fact that Chaos Space Marines are a better melee army than a shooting one most of the time.

The units which benefit most from this are your more durable infantry: Chosen, Terminators, and Obliterators in particular can make quite a bit out of the extra durability.

Iron Warriors Chaos Lord and Space Marines. Credit: SRM

Enhancements

There are a few interesting options here to consider. None are generically good; they’re more options you have to build around a bit. The good news is that they’re all pretty inexpensive. Iron Artifice is great for turning a Chaos Lord into an anti-vehicle monster, while the Bastion Plate can give you a solid durability buff on a unit of Chosen or Terminators.

Bastion Plate (10 points) – Goes on a non-JUMP PACK Chaos Lord. Once per battle round, when you fail a save for the bearer’s unit, you can change the damage characteristic of that attack to 0. This is solid. You want this on a Terminator Chaos Lord, where it can combine with Iron Fortitude to create a really tough unit that can weather a bit more damage. This is also the good version of the rule, letting you wait for a failed save to use it, rather than wound allocation.
Warp Tracer (20 points) – In your Shooting phase, after the bearer shoots, pick an enemy unit hit by one or more of those attacks. Until the end of the phase they can’t have the Benefit of Cover. At 20 points this feels overcosted, but being able to tag certain units for a +1 AP boost is pretty solid. It’s just hard to make it work with the existing character arsenal for Chaos Space Marines. This will do its best work when you combine it with Obliterators, who want to ignore cover when firing Indirect.
Ironbound Enmity (15 points) – Each time the bearer makes an attack while within range of an objective marker, add 1 to the Wound roll. This is okay. It's going to do its best work on one of the big characters, and it’s a good way to “have your cake and eat it too” with a Daemon Prince, where you can give them this and the Mark of Nurgle for +1 Toughness, or double up on this and the Mark of Khorne for S10 attacks with +1 to wound, letting you more effectively hunt vehicles.
Iron Artifice (10 points) – Infantry model only. The bearer’s weapons have [ANTI-VEHICLE 4+] and [ANTI-FORTIFICATION 4+]. Ignore the fortifications part. The best place for this is on a Daemon Hammer Chaos Lord or a Master of Executions, who can throw out dev wounds against vehicle targets on a 4+. It's also not bad on a Terminator Sorcerer, who has his own Dev Wounds psychic attack to throw out.

Credit: Robert "TheChirurgeon" Jones

Stratagems

The Fellhammer Siege-Host Stratagems aren’t amazing but they’re pretty useful, and they offer a mix of defensive boosts, spiteful retaliation, and a couple of solid damage buffs which rely on either your unit or the target being below half-strength. The big challenge here is that these tend to mostly be reactive.

Persistent Assailants (Battle Tactic, 1 CP) – Pick a unit in your army that was picked as the target of an attack in the Fight phase, but hasn’t fought yet. For the rest of the phase, that unit can re-roll hit rolls, and if your unit is below half-strength, they can re-roll wound rolls instead. This is a decent retaliatory move, and a solid consolation prize for eating some melee attacks before you strike back. You don't generally want to be getting hit first, but if you're going to get hit first this can be a pretty big deal. It's situational but re-rolling all wound rolls is something Terminators don't normally get.
Brutal Attrition (Epic Deed, 1 CP) – Used in the Fight phase, after an enemy unit picks its targets. Pick one non-DAMNED Infantry unit in your army that was picked as a target; after the attacking unit finishes making its attacks, roll one D6 for each attack, to a maximum of 6D6 per attacking unit. For each 4+ you roll, the attacking unit takes 1 mortal wound. Getting free grenades back on an enemy unit each time they swing at you - and most of the time you’ll take six or more attacks - and the ability to punish opponents for trying to charge you with multiple units is pretty solid. This is really great for putting extra mortals on vehicles, where something like a Rogal Dorn or Land Raider will throw out 6 attacks that do nothing, but then eat mortals in response.
Pitiless Cannonade (Battle Tactic, 1 CP) – Used in your Shooting phase. Gives a unit critical hits on a 5+ against units that are below Half-Strength. Situational, but very solid since you’ll know full well when this can be used. Remember that this causes your Dark Pacts to trigger on a 5+ and if you have a Helbrute around you’ll snag both effects. Good for finishing off that unit that might otherwise have lived with a single wound left and best with combined with Sustained Hits and re-rolls.
Point-Blank Destruction (Battle Tactic, 1 CP) – Used in the Shooting phase on a unit that’s within Engagement Range of an enemy unit. Until the end of the phase, your unit’s ranged weapons (except for the blast weapons) gain the PISTOL ability. This can be yet another solid way to make an opponent regret trying to tie you up, though it won’t get you out of combat in time to move. I particularly like it on Obliterators, who otherwise don’t have a way to shoot out of combat since they lack Big Guns Never Tire, and it's absolute fire on Rubrics, Noise Marines, and Plague Marines armed with torrent weapons. It's also decent on a unit of Terminators locked in combat with other infantry. Being able to shoot your way out of combat and then charge something is huge.
Steadfast Determination (Strategic Ploy, 1 CP) – Used in your opponent’s Shooting phase to give a non-DAMNED unit a 5+ Feel No Pain until the end of the phase. This is pretty good, and it’s incredible on 3-wound infantry like Terminators where it can help them power through attacks with Devastating Wounds. It looks even better in the wake of the nerfs to Armour of Contempt.
Siegecraft (Strategic Ploy, 1 CP) – Used at the start of your opponent’s Charge phase. Pick a unit in your army and until the end of the phase, if an enemy unit picks your unit as a charge target, they get -2 to the Charge rolls (this isn’t cumulative with other negative modifiers). This was previously a Stratagem on Death Guard in 9th edition and it’s pretty good. Having to use it before charges are declared is a bit of a downer, but the net effect is so good that it makes up for it. It’s a great way to dodge pesky 9” Deep strike charges and great for causing multiple charges against the same unit to fail. Sometimes it’s just about preventing an opponent from getting to an objective.

Warpsmith. Credit: Rockfish

Playing This Detachment

The biggest problem that the Fellhammer Siege-Host Detachment has is that it’s highly reactive. Almost all of its stratagems require putting the game firmly in your opponent’s hands and that’s really not what you want to be doing as a Chaos Space Marines player. Doing mortal wounds or getting re-rolls after you’re being hit isn’t nearly as satisfying or useful as killing things before they get to hit you in combat. Likewise, shooting in combat with PISTOL weapons isn’t nearly as good as being able to just Fall Back and shoot, something you can get access to in other Detachments. Chaos Space Marines tend to be an offensively-focused army of glass cannons, and the defensive buffs here don't do enough to change that, while also not giving you the kinds of melee boosts you need to hack through your opponents' more durable threats.

That said, there's plenty you can get out of running this if you want to go with a more grinding advance playstyle and the key to that is running Terminators and Chosen, the faction's most durable 3-wound units. Terminators are already one of your most durable units, and get the most out of buffs like the Bastion Plate and Steadfast Determination Stratagems. They're also a solid unit for shooting your way out of combat with Point-Blank Destruction. Chosen with Bile have a similar level of durability, with three wounds apiece and Toughness 5, plus the ability to advance and charge baked in. Abaddon is also a good feature in this Detachment, giving key units access to much-needed re-rolls or a 4+ invulnerable save to nearby Infantry units (again, this is for your Chosen).

Playing the Siege-Host doesn't mean that you have to build around a reactive play style, but it does want you to prioritize slower, more durable units and ranged output. There's a lot of value here for cult marines like Plague Marines, Rubrics, and Noise Marines, and the latter two really like to be able to shoot their way out of combat with a few bursts of ranged weapons. Being able to shrug off shooting in the open is pretty solid and we've seen some lists do well with this detachment, albeit on a limited basis - there are just typically better options out there if you want to run the same units.

Strengths

Durability. This Detachment offers a solid durability buff against incoming shooting, and it's great for keeping key units around and works on infantry and vehicles
Terminators. There are some good buffs here for Terminators, who really want the Detachment durability buff.
Cult Units. The buffs here are great on Rubrics, Noise Marines, and Plague Marines.

Weaknesses

Melee. That defensive buff doesn't work in melee, making you vulnerable to being hacked to pieces by melee armies.
Melee Buffs. The lack of melee buffs pushes you away from some of the faction's best units and makes you even more vulnerable when getting charged.
Defensive Focus. There's very little here in the way of offensive buffs and that means your game plan will be more reactionary than usual.

Forgefiend. Credit: Rockfish

A Sample List

The Fellhammer Siege Host isn't the best way to run the faction, and so it's hard to come by successful versions of the list, but there have been some solid examples recently which point to the fact that a skilled player can take a list with this detachment to a decent result.

Nick Toomey's List

Nick took this list to a 4-0-1, fourth place finish at the Rise of the Empire GT in mid-December and after the points increase to Fabius Bile in the Q4 dataslate (though this is offset a bit by the fact that he runs a Forgefiend). Nick beat Shadowmark marines, Imperial Knights, Custodes, and Thousand Sons before tying Death Guard in the final round.

Nick's List - Click to Expand

This Detachment Has A 37% Winrate

+++++++++++++++++++++++++++++++++++++++++++++++ + FACTION KEYWORD: Chaos - Chaos Space Marines + DETACHMENT: Fellhammer Siege‑host + TOTAL ARMY POINTS: 2000pts + + WARLORD: Char1: Abaddon the Despoiler + ENHANCEMENT: Bastion Plate (on Char5: Chaos Lord in Terminator Armour) & Ironbound Enmity (on Char6: Lord Discordant on Helstalker) + NUMBER OF UNITS: 13 + SECONDARY: - Bring It Down: (2x2) - Assassination: 6 Characters +++++++++++++++++++++++++++++++++++++++++++++++

OTHER DATASHEETS

Char1: 1x Abaddon the Despoiler (270 pts) 1 with Drach'nyen, Talon of Horus • Warlord

Char2: 1x Cypher (90 pts) 1 with Cypher's bolt pistol, Cypher's plasma pistol

Char3: 2x Fabius Bile (100 pts) • 1x Fabius Bile 1 with Rod of Torment, The Chirurgeon, Xyclos needler • Fabius Bile • 1x Surgeon Acolyte 1 with Surgeon Acolyte's tools • Surgeon Acolyte

Char4: 1x Vashtorr the Arkifane (175 pts) 1 with Vashtorr's claw, Vashtorr's hammer

Char5: 1x Chaos Lord in Terminator Armour (95 pts) 1 with Combi-weapon, Chainfist Enhancement: Bastion Plate (+10 pts)

Char6: 1x Lord Discordant on Helstalker (175 pts) 1 with Bladed limbs, Bolt pistol, Impaler chainglaive, Baleflamer, Magma cutter Enhancement: Ironbound Enmity (+15 pts)

10x Cultist Mob (50 pts) • 1x Cultist Champion 1 with Brutal assault weapon, Autopistol • 9x Cultist 9 with Autopistol, Brutal assault weapon

10x Chaos Terminator Squad (360 pts) • 1x Terminator Champion 1 with Chainfist, Combi-weapon • Terminator Champion • 1x Chainfist and combi-weapon 1 with Chainfist, Combi-weapon • Chaos Terminator • 2x Heavy weapon 2 with Power fist, Reaper autocannon • Chaos Terminator • 2x Paired accursed weapons 2 with Paired accursed weapons • Chaos Terminator • 4x Power fist and combi-weapon 4 with Combi-weapon, Power fist • Chaos Terminator

10x Chosen (250 pts) • 1x Chosen Champion 1 with Plasma pistol, Power fist, Boltgun • Chaos icon, Chosen Champion • 9x Chosen 2 with Accursed weapon, Bolt pistol, Boltgun • Chosen 4 with Accursed weapon, Bolt pistol, Combi-weapon • Chosen 2 with Paired accursed weapons, Plasma pistol • Chosen 1 with Boltgun, Plasma pistol, Power fist • Chosen

5x Chosen (125 pts) • 1x Chosen Champion 1 with Plasma pistol, Power fist, Boltgun • Chaos icon, Chosen Champion • 4x Chosen 1 with Accursed weapon, Bolt pistol, Boltgun • Chosen 2 with Accursed weapon, Bolt pistol, Combi-weapon • Chosen 1 with Paired accursed weapons, Plasma pistol • Chosen

10x Traitor Guardsmen Squad (70 pts) • 1x Traitor Sergeant 1 with Power weapon, Corrupted pistol • 9x Guardsman 6 with Close combat weapon, Lasgun 1 with Close combat weapon, Cultist grenade launcher 1 with Close combat weapon, Meltagun 1 with Close combat weapon, Plasma gun

3x Chaos Bikers (70 pts) • 1x Biker Champion 1 with Close combat weapon, Combi-bolter, Power fist • Chaos icon • 2x Biker 2 with Close combat weapon, Combi-bolter, Plasma gun, Astartes chainsword

1x Forgefiend (170 pts) 1 with 2x Ectoplasma cannon, Armoured limbs, Ectoplasma cannon

There's a lot of beef in this list! You've got two very durable 10-man bricks here - Fabius Bile with ten Chosen and the Bastion Plate Terminator Lord with his ten hangers-on give you two T5, -1 to wound bricks which are each capable of blanking one shot per turn, and you have Abaddon paired with another 5-model unit of Terminators. The ten-man unit starts in Deep Strike while Abaddon starts on the table and lends either a 4+ invulnerable save or re-rolls to the nearby Chosen unit as needed. Vashtorr and the Lord Discordant give the army a way to confidently take out vehicles with their upgraded melee profiles, and the Forgefiend is there both as reliable fire support and a way to make sure Vashtorr has Lone Operative at the start of the game.

With no Transports this list is slower than you'd expect for a Chaos Space Marines list. The Bikes and Lord Discordant give it some speed around the table edges but this one's happy to trudge forward and let the opponent move in while using its durability buffs to shrug off incoming fire. That'll be a problem against melee armies, and is likely why the list tied in the final round, where going into three units of Deathshroud Terminators with Lethal Hits and ANTI-INFANTRY guns was likely to cause problems.

Final Thoughts

The Fellhammer Siege-Host is a strange Detachment. It has some solid defensive buffs, but it feels like a set of rules more suited to Death Guard than the current Chaos Space Marines army, whose army rule pushes them more toward aggressive, offensive play and whose datasheets push toward fast melee engagement. Still, with the right units and environment, you can build some very annoying if not super powerful lists here and we've certainly seen players go the distance with a Fellhammer list once or twice before.

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