Breath Weapon (Su): At 1st level, you gain a breath weapon that you can use at will as a standard action. Each time you use your breath weapon, you can choose whether it takes the form of a 15-foot cone or a 30-foot line. This breath weapon deals 1d6 points of fire damage; a successful Reflex save (DC 10 + 1/2 your class level + your Con modifier) halves the damage. As you gain levels, your breath weapon's damage increases, as shown on Table 2-1.
You are immune to the effect of your own breath weapon (but not to other breath weapons that produce similar effects, even those of other dragonfire adepts).
At 10th level, your cone-shaped breath weapon's range doubles to 30 feet, and your line-shaped breath weapon's range doubles to 60 feet.