The visual effects of firestorm looks as if it causes explosions that would deal damage to nearby targets. However upon closer inspection, and use of the ability, the ability does not do damage. Is this a bug or is this intentional? As it seems, the firestorm ability appears to be sub-par when compared with the abilities of the other Battle sprite.
Firestorm is not intended to do damage on deployment until you get the ultimate that makes it make explosions. It's basically a moderate fire Ash of Agni.