Aura of Hellfire


School	Evocation (opposed by Conjuration)
Spell level	Innate level 9. No class learns it from a spellbook
Range	Personal (0 m; 2.25 m when aimed at another creature)
Components	Verbal and somatic
Can be aimed at	yourself or an item
Counts as an attack	Yes. Casting it on someone is a hostile act

How it works

A creature ability, and it cannot be turned off once active. Players have the racial Hellfire Aura instead, which can.
While it is active, the creature gets 100% fire Damage Immunity.
Anyone who hits the creature in melee takes 2d6 + caster level fire damage. Caster level counts up to 40 for this.
It cannot be dispelled.
Creatures inside the aura take 6d6 + caster level fire damage each round. A Fortitude save halves it.