Burning World

Creates a catastrophic fire that affects a sphere of 1 mile around the caster, which applies inflammed  to all creatures within the distance apart from the caster. At the start of each round, all creatures within the effect distance apart from the caster must take a constitution saving throw at disadvantage. On failure, the creature takes 1d8 fire damage and gets inflammed. This fire cannot be affected by any other spell, and cannot be put down.

Inflammed: An inflammed creature loses its action, bonus action and takes 1d8 fire damage on the end of each round. At the start of each round of the creature, it must take a constitution saving throw at disadvantage against the caster. This saving throw is unaffected by Sculpt Spells. If inflammed is applied to creatures already affected by inflammed, the fire damage stacks but other effects don't.