Lesser; 3rd; Eldritch Essence
This eldritch essence invocation allows you to change your eldritch blast into a brimstone blast. A brimstone blast deals fire damage. Any creature struck by a brimstone blast must succeed on a Reflex save or catch on fire, taking 2d6 points of fire damage per round until the duration expires. The fire damage persists for 1 round per five class levels you have. A creature burning in this way never takes more than 2d6 points of fire damage in a round, even if it has been hit by more than one brimstone blast.