Azreth

Great plumes of cursed fire pour out from the tip of your wand, rampaging into shapes of beasts and incinerating anything in their path. Upon casting, the area of the fiendfyre is one 10-foot cube, with the number of 10-foot cubes doubling at the beginning of each of your turns. As long as concentration is maintained, you can arrange any newly added cubes as you wish. Each cube must have at least one face adjacent to the face of another cube. Each creature in the area must make a Dexterity saving throw. It takes 7d10 fire damage on a failed save, or half as much damage on a successful one. A creature takes the same damage when it enters the area for the first time on a turn or ends its turn there. Upon reaching 8 cubes, you must make a DC15 Constitution saving throw to maintain concentration at the beginning of each of your turns. If your concentration is broken after 4 cubes of fiendfyre are active, the spell doesn’t end and rages out of control. The fiendfyre will continue to double at the beginning of each round, until the end of its duration. If you decide to end the spell while you still have concentration, the spell ends as normal and all fiendfyre disappears. The fiendfyre damages objects in the area and ignites flammable objects that aren’t being worn or carried. Even magical objects and defenses are damaged or destroyed by this spell. At Higher Levels. When you cast this spell using a spell slot of 8th level or higher, the damage increases by 2d10 and the concentration DC increases by 1 for each slot level above 7th.