Gotfret de Montbard

One Miracle Die is generated at the start of each Player Turn.

Once per phase, one unit from your army with this ability can perform one Act of Faith using Miracle dice on the following dice rolls:
Advance, Charge, Hit, Wound, Saving throw, Damage; Morale test

There's an ENTIRE PAGE of rules for Acts of Faith/Miracle dice in the Codex on page 91. I'm not typing that in, and you should have them memorized by now, anyway.

Models in this unit have a 6+ invulnerable save.

In your opponent's Psychic phase, this unit can attempt to deny one psychic power as if it were a PSYKER. Each time a Deny the Witch test is take for this unit, roll one D6 instead of 2D6: if the result of that test was an unmodified result of 6, or if it was greater than the result of the Psychic test, that Deny the Witch test is passed.