Ritual of Arcane Might

Every wizard in your army knows this spell-
Summon arcane might, casting value 10: deal 1
mortal wounds to all units on the table (including
friendly units)When casting this spell a wizard
can deal d3 mortal wounds to any number of
friendly units within 3 inches of it and for each
mortal wound caused, add +1 to the casting roll.
You complete this strategic objective if you cast
this spell at least 3 times.
Boon:—
Your wizards have +1 to cast for all future games.