Chaos Cult: The 11th-Edition Chaos Space Marines Cultist Horde Detachment

Each time a Damned unit from your army with the Dark Pacts ability is selected to make a Normal or Advance move, or to declare a charge (excluding units that arrived from Reserves this turn), it can make a Desperate Pact. If it does, until the end of the phase, add 2 inches to the Move characteristic of its models and add 2 to Charge rolls for it.

A Desperate Pact works like the army rule: take a Leadership test first, and on a failure the unit suffers D3 mortal wounds before any effects resolve.

Faction Pack v1.2 rewrote the Keywords section so that Traitor Guardsmen Squad units from your army gain the BATTLELINE keyword, which changes what they can score and hold.

The shape of the detachment falls out of that. It is a movement rule, not a damage rule: cultists that pact move 2 inches further and charge 2 inches further, every phase, for the price of a Leadership test on units whose Leadership is bad. That is a genuine gamble, and it is why four of the six stratagems also let you make a Desperate Pact as part of their effect.

Six, all 1CP, and four of them fold a Desperate Pact into the effect so you get the movement bonus alongside the stratagem.

• Chosen for Glory (Shooting or Fight) — a Damned unit makes a Desperate Pact and re-rolls Hit rolls, plus Wound rolls if the Leadership test did not fail.
• Crazed Focus (Shooting) — a Desperate Pact plus +1 Armour Penetration, and +1 Strength if the test did not fail.
• Infernal Sacrifice (Fight) — a Desperate Pact, the unit takes D3 mortal wounds regardless, and gains +1 Attack on melee weapons, plus +1 Strength if the test did not fail.
• Reckless Haste (Charge) — a Damned unit can declare a charge after Advancing.
• Selfless Demise (Fight) — each destroyed model in a targeted Damned unit inflicts 1 mortal wound on a 6.
• Mortal Thralls (opponent's Shooting) — nominate a targeted Heretic Astartes unit and a friendly Damned unit within 3 inches: while the Damned unit is a legal target, Wound rolls against your Heretic Astartes unit are replaced by the Damned unit suffering mortal wounds equal to the attack's Damage.

Mortal Thralls is the detachment's best trick. It converts a squad of cultists directly into hit points for the unit you actually care about, and against a high-Damage attack it is a spectacular trade.

Every one is Dark Apostle or Damned model only, except the Amulet, which narrows further to Dark Apostle. This is one of the few detachments where your enhancement carrier is a cultist character rather than a marine.

• Cultist's Brand (30 pts) — if every other model in the bearer's unit (excluding Dark Disciples) is Damned, re-roll Advance and Charge rolls. Stacked on the +2 from a Desperate Pact, this is a very fast horde.
• Incendiary Goad (25 pts) — while the unit is below Starting Strength, +1 Strength on Damned melee weapons, and +1 Attack as well while it is Below Half-strength. A horde that gets angrier as it dies.
• Amulet of Tainted Vigour (20 pts) — Dark Apostle only: return up to D3 destroyed non-Character Damned models each Command phase.
• Warped Foresight (10 pts) — while the bearer leads a unit with Scouts 6 inches, every model in that unit has Scouts 6 inches. Rewritten by Faction Pack v1.2.

(Points come from the Munitorum Field Manual and move with updates; confirm in the app.)

• Traitor Guardsmen Squad — the pack made them Battleline in this detachment, and rewrote their Twisted Defence Force ability to a flat +1 Save against ranged attacks while within range of an objective.
• Chaos Cultists — cheap Damned bodies to pact with and to feed Mortal Thralls.
• Accursed Cultists — the pack rewrote their Howling Horde ability so losing a model to shooting lets the unit make a D6-inch surge move.
• Dark Commune — Damned characters that can carry Cultist's Brand, Incendiary Goad or Warped Foresight without spending your Dark Apostle.
• Dark Apostle — the only legal Amulet of Tainted Vigour bearer, and the model that keeps a cultist block on the table.
• Legionaries — Mortal Thralls only pays off if you have a Heretic Astartes unit worth protecting behind the cultists.

Take it when your collection has a real cultist and Traitor Guardsmen core and you want to play a wide, fast, expendable army that smothers objectives. Making Traitor Guardsmen Battleline is a genuine scoring upgrade, and Mortal Thralls turns your cheapest models into ablative armour for your most expensive ones.

Be clear-eyed about the limits. The detachment rule is a movement bonus gated on a Leadership test taken by units with poor Leadership, so you will fail some and eat D3 mortal wounds on a unit that was already fragile. It also does nothing at all for your Heretic Astartes marines: five of the six stratagems name Damned units, and every enhancement is Dark Apostle or Damned. A marine-heavy list is paying 2 DP for Mortal Thralls alone.

Sample gameplan: field two or three cultist blocks and a Traitor Guardsmen Squad on the objectives. Put Cultist's Brand on a Dark Commune character leading a pure cultist unit, and Amulet of Tainted Vigour on the Dark Apostle. Make Desperate Pacts on the moves that matter and skip them when a unit is already in position. Spend Crazed Focus or Chosen for Glory on the objective fight, and hold a command point for Mortal Thralls the moment a high-Damage weapon aims at your marines.