ST Boon of Elemental Prowess

You gain the following benefits.

Ability Score Increase. Increase your Intelligence, Wisdom or Charisma score by 1, to a maximum of 30.

Overcome Defenses. The Fire, Cold, and Lightning damage you deal always ignores Resistance.

Overwhelming Strike. When you roll a 20 on the d20 for an attack roll, you can deal extra damage to the target equal to the ability score increased by this feat. The extra damage’s type is the same as the attack’s type.

Elemental Mastery. When you cast a spell that requires a save, if that spell does fire, cold, or lightning damage, and a target with immunity fails by 5 or more you ignore immunity for that spell. If a target with resistance fails by 5 or more you ignore resistance for that spell. If a target with neither immunity or resistance fails by 5 or more, they are vulnerable to that spell.