A creature takes 2d6 damage on a failed save, and half as much damage on a successful one. The DC of this saving throw is 8 + your Constitution modifier + your proficiency bonus.

When you use your breath weapon, all creatures in the area must make a saving throw, the type of which is determined by your ancestry. It deals damage in an area according to your ancestry. You can use your action to exhale destructive energy. Choose a type of dragon from the below list this determines the damage and area of your breath weapon, and the type of resistance you gain. You are distantly related to a particular kind of dragon. Dragonborn are taller and heavier than humans, standing well over 6 feet tall and averaging almost 250 pounds. Some rare few choose to devote themselves to lesser dragon deities, such as Chronepsis (Neutral), and fewer still choose to worship Io, the Ninefold Dragon, who is all alignments at once. More side with Bahamut than Tiamat (whose non-dragon followers are mostly kobolds), but villainous dragonborn can be quite terrible indeed. Dragonborn tend towards extremes, making a conscious choice for one side or the other between Good and Evil (represented by Bahamut and Tiamat, respectively). They walk hours after hatching, attain the size and development of a 10-year-old human child by the age of 3, and reach adulthood by 15.

D&d crystal race