Fires of the Covenant

Roll 2 D6. If the result is greater than the
Converted Mana Cost, Select one enemy unit
within engagement range of this unit. Roll 1 D6
per model in that unit. For every roll of 4+ deal
1 mortal wound to that unit. You can only target
the same unit once per game.
"Drawing upon his pledges of duty and the bonds of
his brotherhood, the psyker release a fiery conflagration of death"
-Grey Knights, Datacards