Chaplain Cassius

When choosing an army, all models in the same Detachment or Formation must be drawn from the same Chapter.  If a unit's datasheet contains a Chapter in brackets after the Chapter Tactics special rule - for example, "Chapter Tactics (Ultramarines)" - the unit must always be drawn from this Chapter, and therefore cannot be included in a Detachment or Formation with any units that are drawn from other Chapters. All models drawn from a given Chapter benefit from that Chapter's Special Rule. If a unit contains models drawn from two different Chapters, it counts as from neither Chapter, and thus benefits from neither Chapter Tactic.

When a model with this special rule suffers an unsaved Wound, it can make a special Feel No Pain roll to avoid being wounded (this is not a saving throw and so can be used against attacks that state that 'no saves of any kind are allowed', for example those inflicted by Perils of the Warp).

Feel No Pain saves may not be taken against Destroyer attacks or against unsaved Wounds that have the Instant Death special rule.

Roll a D6 each time an unsaved Wound is suffered. On a 4 or less, you must take the Wound as normal. On a 5+, the unsaved  Wound is discounted - treat it as having been saved.

If a unit has the Feel No Pain special rule with a number in brackets afterwards -Feel No Pain (6+), for example - then the number in brackets is the D6 result needed to discount the Wound.

Independent characters can join other units.  They cannot, however, join units that contain vehicles or Monstrous Creatures.  They can join other Independent Characters, though, to form a powerful multi-character unit!  Independent Characters pass Look Out, Sir rolls on a 2+. A unit that contains one or more Independent Characters does not need a double 1 to Regroup if reduced to below 25% of its starting numbres, but instead tests as if it had at least 25% remaining.

Full details in BRB. Rule too long to copy verbatim.

A unit containing one or more models with the Zealot special rule automatically passes Pinning, Fear and Regroup tests and Morale checks, but cannot Go to Ground and cannot choose to fail a Morale check due to the Our Weapons Are Useless rule. If a unit gains the Zealot special rule when it has Gone to Ground, all the effects of Go to Ground are immediately cancelled.

In addition, units containing one or more models with the Zealot special rule re-roll all failed To Hit rolls during the first round of each close combat - they do not get to re-roll failed To Hit rolls in subsequent rounds.

This rule is often presented as Preferred Enemy (X) where X identifies a specific type of foe. If the special rule does not specify a type of foe, then everyone is a Preferred Enemy of the unit. A unit that contains at least one model with this special rule re-rolls failed To Hit and To Wound rolls of 1 if attacking its Preferred Enemy. This applies both to shooting and close combat attacks.

A model that suffers one or more unsaved Wounds from a weapon with this special rule is reduced to Initiative 1 until the end of the following Assault phase.