HeapThaumaturgist said:Warmage description itself in C.Arcane says that if the single spell creates multiple damaging "things", only one of them gets the edge.
So 5th-level Magic Missile, only 1 of the 3 missiles gets the edge damage.
With 7th level Scorching Ray, only 1 of the 2 rays gets the edge damage.
With a fireball, you add the edge to the total damage dealt, for instance, instead of to each orc caught in the fireball.
--fje