A dragon has natural defences, add your strength bonus to your AC when not wearing any kind of armour.  

Your lineage stems from a dragon progenitor. Choose the kind of dragon from the Draconic Ancestors table. Your choice affects your Breath Weapon and Damage Resistance traits as well as your appearance.

When you take the Attack action on your turn, you can replace one of your attacks with an exhalation of magical energy in either a 60-foot Cone or a 100-foot Line that is 10 feet wide (choose the shape each time). Each creature in that area must make a Dexterity saving throw (DC 8 plus your Constitution modifier and Proficiency Bonus). On a failed save, a creature takes 4d10 damage of the type determined by your Draconic Ancestry trait. On a successful save, a creature takes half as much damage. This damage increases by 2d10 when you reach character levels 5 (8d10), 11 (10d10), 17 (12d10)

You can use this Breath Weapon a number of times equal to your Proficiency Bonus, and you regain all expended uses when you finish a Long Rest.

You have Resistance to the damage type determined by your Draconic Ancestry trait.

You have Darkvision with a range of 60 feet.