Level
7th
Casting Time
1 Action
Range/Area
150 ft.
(10 ft. )
Components
V, S
Duration
Instantaneous
School
Evocation
Attack/Save
DEX Save
Damage/Effect
Fire
A storm of fire appears within range. The area of the storm consists of up to ten 10-foot Cubes, which you arrange as you like. Each Cube must be contiguous with at least one other Cube. Each creature in the area makes a Dexterity saving throw, taking 7d10 Fire damage on a failed save or half as much damage on a successful one.
Flammable objects in the area that aren’t being worn or carried start burning.
cool
lit
Can you place the cubes diagonal to each other so that just the corners are touching?
Or do the faces have to be overlapping?
Given the way Cube AoEs are defined, I think you probably do need to have some overlap of the faces. But keep in mind that there's nothing saying the entire face needs to touch.
Sorcerers can cast this. Be a Storm Sorcerer or Draconic Bloodline (blue or bronze dragon ancestry) and take Transmuted Spell. Multiclass into Tempest Domain Cleric for 2 levels. Transmute this spell to deal lightning or thunder damage and use Destructive Wrath with this spell. Multiclassing into Cleric also grants you heavy armor, 3 extra cantrips, and the bless spell.