Arsonist

Origin Feat

Affinity to fire: You learn the spell Create Bonfire or Produce Flame, and Hellish Rebuke. You can cast these using your Spell Casting Ability modifier or Constitution, if you are not a spellcaster. You can cast Hellish Rebuke once per Long Rest without a spell slot on a level equal to your Proficiency Bonus – 1.

Backdraft: When you roll a natural 1 on a d20 test, you immediately cast Create Bonfire or Produce Flame (the spell attack option) as a reaction centered on a random target within 30 feet. If no valid target exists, it centers on you.
You can choose to lean into it once per short or long rest: When you roll a nat 1, you can instead cast a fire spell you know at a level equal to your proficiency bonus or lower as part of that reaction, instead of its regular casting time.