You mark several allies with a flaming rune. This rune does not cause damage, and sheds light as if it were a torch. While the firebrand burns, any creature it marks is immune to damage from any fire spell you cast. All of the target's weapons (both natural and manufactured) inflict +1d6 points of fire damage on a hit (this bonus fire damage stacks with any amount of fire damage a creature's weapons might already inflict). At any point during the spell's duration, a creature bearing a firebrand can launch a beam of fire at any target within 30 feet as a swift action. This ray requires a ranged touch attack to hit and deals 6d6 points of fire damage. Once a creature uses its firebrand to fire a ray in this manner, the effects of the spell end for that creature.