Your hands are constantly on fire allowing you to enhance your punches, your unarmed strike deals 1D6 + str fire damage and at 3rd level you learn the firebolt cantrip

You shed light in a 60 ft radius turning dim light into bright light and darkness into dim light

While you are grappling a creature that is your current size or smaller, you may use your bonus action to open your ribs place them in your chest, if you shrink while entrapping a creature and that creature is now a larger size than you, it automatically escapes. While you are entrapping a creature, your movement speed is halved and you have disadvantage on dexterity saving throws, however you can freely use both your arms and the creature you are entrapping is restrained. At the start of the creature's turn it takes 2 D6 fire damage and can make a strength saving throw with a DC of 8 + your proficiency bonus + your strength modifier, on a successful save it escapes your restraints, otherwise it remains restrained. You can choose to release them at any time. While a creature is entrapped by you it benefits from the effects of half cover and any missed attacks against it hit you instead. The number of times you can use this ability is equal to your proficiency modifier and any expended uses are regained upon a short rest.

At 5th level the damage increases to 3D6

At 11th level the damage increases to 4D6

At 17th level the damage increases to 5D6

Your strength is increased by 2 and your constitution is increased by 1

You gain resistance to fire damage

You are vulnerable to cold damage