World on Fire
Ability Strength mods affect the damage of Fireball, Fire Blast and World on Fire as well as the damage multiplier of Accelerant. The chance to set enemies on fire with World on Fire is also affected by these mods. The extra Heat damage you gain by shooting through Fire Blast’s flames is not affected. Ability Range mods affect the range of Accelerant and World on Fire. Ability Duration mods affect the duration of Accelerant’s cast speed bonus, the ring duration of Fire Blast and the energy drain of World on Fire.
So, all things considered, here are some builds you may want to try on your Ember: