Burning Frostfire

(Originally designed for a phoenix sorcerer) A powerful, magical frost creature shot you with a magical icicle and brought you all too close to death. Your phoenix nature was suppressed and instead of returning to 1hp, you stabilized but remained down. Nobody could heal you, you had to sleep it off. If anyone inspected you they didn't find a wound, just a blue scar on your chest. Pulsating... your heart rate slowing down, your inner fire fighting the cursed frost magic. You awoke in 2 days and felt different, torn... the energies still fighting within you.

• Any spell with the fire of cold damage type is changed into frostfire. If a creature is immune to one of these, it takes 3/4 (75%) of the damage.
• To make the spell purely fire or frost, you must use your bonus action to concentrate. Every 2 spells you change and fight this part of yourself, you gain an exhaustion level.
• If you have fire resistance make it 3/4, rounding down and gain cold resistance 3/4. (if you had fire resistance 5, you now have fire and cold resistance 3)
• If you play with fire (prestidigitation), it will burn partially blue, the flame won't be as strong. If you use this to toy with ice, it will move, but melt in time.
• Burning ice - if you start a fire with your new abilities, it cannot be put out with water.