The Cult's Psyche

Use this Stratagem before the battle. Select one
MAGUS unit from your army. That unit
can attempt to manifest one addtional psychic
power in your Psychic phase. When a Psychic
test is taken for this unit, add 1 to the total for
any friendly PSYKER units within 3"
(to a maximum of +3). You can only use this Stratagem once per battle.