Your Strength score increases by 2 and either your Intelligence or Wisdom score increases by 1.

Adamantine Dragonborn's age the same rate as others but the difference is that they live to be around 120 instead.

Adamantine Dragonborns are perhaps the mightiest of Dragonborn kind. They are the epitome of good, sacrificing whatever is necessary for the common good of intelligent creatures everywhere.

Adamantine Dragonborn's are taller, broader and heavier than other Dragonborns, standing well over 7 to 8 feet tall and averaging almost 300 pounds. Your size is Medium.

Your base walking speed is 30 feet.

You have a claw, bite and tail attack. You are proficient with all three. Your bite and tail attacks do 1d6+Str and your claw attacks do 1d4+Str. If you attack with either a weapon, bite or tail attack as an action, you can do a claw attack as a bonus action with disadvantage. 

The Dragonborn exhales a 15-foot cone of sonic energy. Each creature in the area must make a make a Constitution saving throw. The DC for this saving throw equals 8 + your Strength modifier + your proficiency bonus. A creature takes 2d6 thunder damage on a failed save, and half as much damage on a successful one. The damage increases to 3d6 at 6th level, 4d6 at 11th level, and 5d6 at 16th level. After you use your breath weapon, you can’t use it again until you complete a short or long rest. 

You have resistance to Thunder damage.

Your scales are as strong as the metal your named after. your AC is 13 + your Dexterity modifier. You can use your natural armor to determine your AC if the armor you wear would leave you with a lower AC. A shield’s benefits apply as normal while you use your natural armor.

You can speak, read, and write Common and Draconic. Draconic is thought to be one of the oldest languages and is often used in the study of magic. The language sounds harsh to most other creatures and includes numerous hard consonants and sibilants.