Spawn of Mephistopheles

The arcane power of Mephistopheles courses through your blood, granting you the power to deal Hellfire damage in place of Fire damage on any of your spells. Hellfire glows white and its temperature exceeds that of any other form of fire. Protection from heat, including fire immunity, becomes worthless against it.

For one Sorcery Point, you can imbue a spell that does fire damage with Hellfire, negating Fire Resistance and Fire Immunity.

Hellfire also can be used more effectively on non-magical, non-living objects. Against such objects, roll double the damage dice for the spell as if it were a critical hit.