You gain breath weapons and fire resistance because you are descended from brass dragons.

When you take the attack action on your turn, you can replace one of your attacks with an exhalation of raging fire in a 5 by 30 ft. line. Each creature in that area must make a Dexterity saving throw. The DC for this saving throw equals 8 + your Constitution modifier + your proficiency bonus. On a failed save, a creature takes 1d10 fire damage. On a successful save, a creature takes half as much damage. This damage increases by 1d10 when you reach character levels 5 (2d10), 11 (3d10), and 17 (4d10).

You can use your fire breath a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

You have fire resistance.

At 5th level, you gain a second breath weapon. When you take the attack action on your turn, you can replace one of your attacks with an exhalation in a 5 by 30 ft. line. The save DC for this breath is 8 + your Constitution modifier + your proficiency bonus. Whenever you use this trait, choose one:

• Enervating Breath. Each creature in the line must succeed on a Constitution saving throw or become incapacitated until the start of your next turn.

• Repulsion Breath. Each creature in the line must succeed on a Strength saving throw or be pushed 20 feet away from you and be knocked prone.

Once you use your metallic breath weapon, you can't do so again until you finish a long rest.