Inferno Sorcery

Your innate magic comes from the power of elemental fire. Whatever the case, the magic of the info permeates your being and burns in your chest.

Blaze Speaker

The arcane magic you command is infused with elemental fire and hellfire. You can speak, read, and write Primordial. 

Kindle Magic

Starting at 1st level,  you  learn the fire bolt cantrip, drawing from the fiery well within you. 

Blazing Embers

At 6th level, you gain resistance to fire damage. In addition, whenever you start casting a spell of 1st level or higher that deals fire damage, embers erupts from you. This eruption causes creatures of your choice that you can see within 10 feet of you to take fire damage (choose each time this ability activates) equal to half your sorcerer level.

Flame Dancer

At 6th level, you gain the ability to manipulate fire around you.  As an action, you can fuel or diminish any fire you can see within 60 feet of you.  You cannot, however, cause it to spread to nearby objects.

You also gain the power to hold fire in your hands. 

This fire cannot be thrown, but if you strike a creature or object with a lit hand or fist, it counts as an unarmed strike, you are considered proficient, and it deals fire damage.

Searing Fury

Starting at 14th level, when you are hit by a melee attack, you can use your reaction to deal lightning damage to the attacker. The damage equals your sorcerer level.  You must make a Constitution saving throw against your sorcerer spell save DC. On a failed save,  you radiate a flaming aura that attacks disadvantage against hitting you to avoid your searing flames for a round. 

Inferno

At 18th level, you gain immunity to fire damage and gain the ability to walk through flames and lava without incident. 

Used to the burning heat, your fire magic burns hotter. When dealing fire damage through your magic, targets with immunity to fire are resistant to your flames instead. Targets with resistance to fire now take normal fire damage and targets hat do not have resistance or immunity to fire damage as if they have vulnerability to fire damage.