Dragon Heart

A draconic bloodline or magical connection to dragons (such as being a Dragonborn or a Sorcerer with the Draconic Bloodline).

Your connection to the dragons changed your heart, now functioning as a magical core just like for dragons, it allows you to harness more of your draconic traits.   Increase your Intelligence, Wisdom, or Charisma score by 1, to a maximum of 20.   Draconic Endurance. When you take damage of the type associated with your draconic archetype, you can use your reaction to become immune to that damage type until the start of your next turn.
Additionally, when you fail a Constitution saving throw to maintain concentration on a spell, you can use your reaction to succeed instead. Once you use either of these features, you can't use them again until you finish a long rest.   Draconic Breath. You learn the Dragon's Breath spell. You can cast it once without expending a spell slot or providing its components, but when you do, you must target yourself and choose the damage type associated with your draconic archetype. Once you cast the spell in this way, you can't do so again until you finish a long rest. You can also cast this spell using spell slots you have of the appropriate level. The spellcasting ability for this spell is the ability increased by this feat.