ANATHEMA PSYKANA units from your army gain the following the ability:
Null Aegis (Aura): While an ADEPTUS CUSTODES unit is within 6" of this unit, models in that unit have the Feel No Pain 5+ ability against Psychic Attacks and mortal wounds.
All other ADEPTUS CUSTODES units from your army gain the following ability:
Deadly Unity (Aura): While an ANATHEMA PSYKANA unit is within 6" of this unit, each time a model in that ANATHEMA PSYKANA unit makes an attack, add 1 to the Hit roll.