Poison Blades

"Attacks made with the Precision (X) Special Rule are allocated by the Attacking Player, not the Defender."
When any Hit Test is made for an attack with the Precision (X) Special Rule, if the result of the Dice roll, before any modifiers are applied, is equal to or great than the value of X attached to this variant of the Precision (X) Special Rule, then if a Hit is inflicted by that roll, that Hit becomes a 'Precision Hit'.

These Precision Hits must form a separate Fire Group or Strike Group. Wound Tests are made as normal for Precision Hits and cause Precision wounds. In Step 8 of the Shooting Attack process or Step 7 of the Initiative Step sequence, when selecting a Target Model for a Fire Group or Strike Group that is made up of Precision wounds, the Target Model is not selected using the normal Rules. Instead the attacking Player chooses which Model in the Target Unit will be the Target Model, and may select any Model that is a part of that Unit.

Note that Models Engaged in a Challenge cannot use this Special Rule to allocate Hits to any Model other than the enemy Model that is Engaged in the same Challenge and that any attacks which are made as Snap Shots, or for Weapons or attacks that have either the Blast (X) , Barrage (X), Template or Reaping Blow (X) Special Rules, may never trigger the Precision (X) Special Rule no matter what the result of the Hit Test is.

"A Weapon with the Poisoned (X) Special Rule has a chance to cause a wound regardless of the target's Toughness Characteristic."
When making Wound Tests for Hits that have the Poisoned (X) Special Rule, if the result of any Dice rolled is equal to or greater than the value of X attached to the specific variant of this Special Rule then a wound is caused automatically, regardless of the Toughness Characteristic used to determine the Target Number. A Hit that has this Special Rule may still inflict a wound by passing a Wound Test as normal, instead of using this Special Rule, but never inflicts more than 1 wound if it would both pass the Wound Test and trigger the Poisoned (X) Special Rule. Wounds caused using the Poisoned (X) Special Rule retain the AP and Damage Characteristics of the Weapon and Saving Throws and Damage Mitigation Tests may be made to discard them as normal. The Poisoned (X) Special Rule has no effect on Models that have the Vehicle Type, and limited effect on Models with the Automata or Walker Types (See the Rules for Walkers and Automata in the Warhammer: The Horus Heresy - Age of Darkness Rulebook).

"With a Weapon that has a Breaching (X) Special Rule there is a chance that a Wound Test may result in the Wound ignoring Armour Saves."
When any Wound Test is made for an attack with the Breaching (X) Special Rule, if the result of the Dice roll, before any modifiers are applied, is equal to or greater than the value of X attached to this variant of the Breaching (X) Special Rule, then if a wound is inflicted by that Wound Test, that wound becomes a 'Breaching Wound'.

A Breaching Wound is always treated as having an AP of 2 regardless of the Characteristics of the Weapon used to make the attack.

"A Weapon with the Limited (X) Special Rule can only be used to attack a limited number of times per Battle."
A Weapon with the Limited (X) Special Rule may only be used to make attacks as part of a Shooting Attack or Combat a number of times equal to the value of X attached to the specific variant of the Special Rule. Each time is used to make attacks, the Firepower Characteristic or Attacks Modifier Characteristic of the Weapon not modified by this Special Rule, only the number of times it may be selected in a given Battle.