Excelsis

Once per phase, when you pick a friendly unit to shoot or fight, you can say that the attack has been prophecied. If you do so, roll a dice. On a 1, subtract 1 from hit rolls for attacks made by that unit in that phase. On a 2-6, add 1 to hit rolls for attacks made by that unit in that phase.

An Excelsis army must be from Ghur.

You can use this command ability at the start of the combat phase. If you do so, pick 1 friendly EXCELSIS unit wholly within 12" of a friendly EXCELSIS HERO. If the unmodified save roll for an attack that targets that unit is that combat phase is 6, the attacking unit suffers 1 mortal wound after all of its attacks have been resolved.