Pheonix Blood

Your ancestors were blessed by the pheonix, your bloodline being linked to the fiery beast. Your magic is focused on the destructive power of fire and the suffocating force of ash. As you gain more favor with your avian matriarch, you gain more control over fire, ash. along with a fiery familiar and eventually the power of purification through flames.

Burning Soul

You have a deep connection with the magics of the phoenix, exemplified in your control over fire. You can speak, read and write Primordial. Additionally, you suffer no penalties for walking on fire or heated terrain and are adapted to live in hot climates. As well as that, you can now access all spells that deal fire damage. You can learn them as if they were sorcerer spells, and they count as sorcerer spells for the purposes of all effects.

Flaming Companion

Also at 1st level, you learn the Find Familiar spell and it counts as a sorcerer spell for the purposes of all effects. You have the same restrictions of the spell when you use it, except your familiar is made out of fire, and becomes a elemental instead of a fey, fiend or celestial.

Formed Flame

Starting at 6th level, you gain resistance to fire damage. Whenever you cast a spell that deals firedamage, add your Charisma modifier to that damage. Additionally, you can cast Flame Blade once per long rest.

Wings of the Pheonix

At 14th level, the flames within you become enhanced when your blood. When you are hit by a melee attack, you can use your reaction to deal fire damage to the attacker equal to half your sorcerer level, rounded down. You can also as part of the same action sprout temporary wings and fly up to 30 feet backwards, not provoking opportunity attacks, and dealing 2d8 fire damage in a 15 foot cone in front of you before you take off. You can do this once per long rest. 

You also gain +2 to hit with any spell that deals fire damage if it has an attack roll and anyone that must make a saving throw against fire damage spells has -2.

Ashes to Ashes

At 18th level, you are at the peak of what your inner fire can give you. When you die, you and everything you're carrying instead turn to ash, except anything that can't be burned. After 7 days, you are reborn somewhere within 1000 miles of where you died. You have all your equipment back with you, except anything that can't be burned.

You also gain a flight speed of 30 feet, and as a bonus action on your movement, can fly in a 20 foot long straight line, the ground beneath you becoming difficult terrain to anything without fire resistance or immunity. Anything stepping onto this terrain for the first time or ending it's turn whilst on it takes 1d8 fire damage. This damage ignores resistances and immunities.