Roboute Guilliman, Primarch of the Ultramarines

Friendly units from the Armies of the Imperium re-roll failed Morale checks and Fear and Pinning tests while Guilliman is on the battlefield.

Roboute Guilliman's Leadership is not subject to negative modifiers of any kind and he may re-roll failed Deny the Witch tests.

You can choose to enact the Devastator, Assault and Tactical Doctrines once each per game (in addition to any you can already use).  When one of these Combat Doctrines is enacted, all Ultramarines models in your army are affected.

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.

A unit composed entirely of models with this special rule can re-roll one or more of the dice when determining Run moves and charge ranges (such as a single D6 from a charge range roll, for example).

If a model with this special rule suffers an unsaved Wound from an attack that inflicts Instant Death, it only reduces its Wounds by 1, instead of automatically reducing its Wounds to 0.

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.

A unit that contains at least one model with this special rule receives a +1 bonus to Deny the Witch tests.

Units containing one or more models with the Fearless special rule automatically pass Pinning, Fear, 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 has Gone to Ground and then gains the Fearless special rule, all the effects of Go to Ground are immediately cancelled.

If a model with this special rule rolls a 6 To Hit with a shooting weapon, that shot is a 'Precision Shot'.

Wounds from Precision Shots are allocated against a model (or models) of your choice in the target unit, as long as it is in range and line of sight of the firer, rather than following the normal rules for Wound allocation. A character that has a Precision Shot Wound allocated to it can still make a Look Out, Sir roll.

Note that Snap Shots and shots from weapons that scatter, or do not roll To Hit, can never be Precision Shots.

If a model with this special rule rolls a 6 To Hit with a Melee weapon, that hit is a 'Precision Strike'.

Wounds from Precision Strikes are allocated against an engaged model (or models) of your choice in the unit you are attacking, rather than following the normal rules for Wound allocation. If a Precision Strike Wound is allocated to a character, they can still make their Look Out, Sir roll.

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.