Blazing Heat in the Sky

"Heed the contract and serve Me, O Tyrant of Flame!
Come, flame of purification, fiery broadsword.
Fire and brimstone surge forth, burn down Sodom,
turn the sinners into the dust of death!"

You gather torrents of flames to release in a blast.
10d12 fire damage with advantage, 12 ft/4 m wide & 65 ft/20 m long range.
All targets are stunned & repelled 19 ft/6 m away.