Conjure Hellfire

You learn the eldritch blast and it gains a damage boost equal to your charisma

Beginning at 1st level, the damage type of your eldritch blast cantrip changes to fire. This damage ignores fire resistance and does half damage to creatures with fire immunity.

Additionally, you gain the ability to temporarily channel greater amounts of hellfire through your own body, at a cost. When you attack with your eldritch blast or a spell of 1st level or higher that does fire damage, you can expend one of your hit dice to add an additional 1d12 fire damage to the roll. The additional damage ignores resistance and immunity to fire damage.

If you use this feature and you have no hit dice left, you take a level of exhaustion.