Replacing your divine connection, you have finalised your pact to some darker force. Your spells that restore Hit Points, instead now only provide Temporary Hit Points, further more any Radiant Damage dealt by spells or by your Channel Divinity is now Fire Damage. Finally, you gain the following benefits.
Whispers from the Fire. You learn the cantrips fire bolt and control flames and can cast them at will. You also gain the spells hellish rebuke, aganazzar's scorcher, and melf's minute meteors and can cast each of them once at their lowest level without expending a spell slot. You regain the ability to cast them in this way when you finish a Long Rest. You can also cast the spell using any spell slots you have. Wisdom is your spellcasting ability for this feat’s spells.
Unrelenting Blaze. Spells you cast ignore resistance to Fire Damage, and when you cast a spell that deals Fire Damage, add your Wisdom modifier to one damage roll of that spell.
Bound to Burn. You gain resistance to fire damage unless it is afflicted by yourself. Furthermore, when you attempt to cast a spell that deals Fire Damage, instead of expending a spell slot you can choose to inflict a number of d8's of fire damage (cannot be resisted) onto yourself. The number of d8s equals 1 + the spells level (so a level 3 fireball would inflict 4d8 irresistible fire damage).