rare enchantment 

Traditions arcane, occult

Cast [>>] somatic, verbal

Range 30 feet; Targets 1 creature

Saving Throw Will; Duration sustained up to 1 minute

You disrupt the connection between a divine caster or deific servitor and their deity, blocking their use of divine power.

If the target fails its save, it is fatigued. For the spell's duration, whenever the target casts a divine spell, you regain 6d6 HP and the target must attempt another Will save with the following effects.

Critical Success The target is unaffected.Success Each target of the divine spell has an outcome one degree of success better than the result it rolled.Failure The divine spell is lost and target is stunned 1.Critical Failure As failure, but the target is stunned for 1 round.

AoE6, page 75.