Your AC Equals 20 + your Dexterity modifier

You are resistant to fire

You can add obsidian to your scales granting 1 temporary hit point per obsidian shard added

Your powerful Tail can be used as a weapon in unarmed strikes dealing 1d6 + Your strength modifier (bludgeoning damage)

Your tail also helps you maintain stability and balance. You have +1 advantage on ability checks made to keep your footing, such as Acrobatics checks to balance or avoid being knocked prone

Your draconic heritage allows you to see in darkness as if it were dim light.

You have Darkvision up to 60 feet.

Your Black Dragon blood grants you immunity to the elemental power of your draconic lineage. 

Also grants you the ability to Spit Acid once every 2 hours

(Black immune to acid)

Your massive, dense frame makes you incredibly strong but unwieldy in water.
Your Strength score increases by 5
Your Constitution score increases by 2

You sink to the bottom in any body of water (cant float)

Your muscular limbs, claws, and tail make you an exceptional climber, able to scale sheer surfaces with ease
You have a climbing speed of 30

Horns crown your head, marking your lineage and intimidating foes in battle.

You gain advantage on Intimidation checks against creatures that can see your horns

At the peak of your draconic power, your latent Dragon blood awakens fully, allowing you to sprout wings and take to the skies.

Starting at 10th level, you can summon a Young Black Dragon You can use this feature once every 2 levels (i.e., at levels 10, 12, 14, etc.).

The dragon acts on your turn and follows your commands. Treat it as a controlled creature, similar to a familiar or ranger’s companion.

Growth: Each time the dragon survives 1 week of adventuring or combat without being killed, it increases in size and gains additional hit points and damage (DM can scale similar to young → adult → ancient dragon progression). The dragon remains until it is dismissed, incapacitated, or killed. You can only have one summoned dragon at a time.

You can sprout wings as a bonus action. You gain a flying speed of 30 feet. While flying, you must have enough space to extend your wings, and you cannot fly while wearing heavy or restrictive armor.

Your Dragon blood surges uncontrollably, your mind is overtaken by primal, draconic fury. You become a terrifying force of destruction, but lose some control over your actions.
When you drop to half your maximum hit points or lower, you automatically enter a berserk state until you regain above half your hit points or you are incapacitated.
While berserk:
You have advantage on Strength checks and Strength saving throws.
You make melee weapon attacks using your Strength modifier, dealing an extra 1d6 damage.
You must attack the nearest creature each turn if able, friend or foe.
You have disadvantage on Intelligence, Wisdom, and Charisma checks.

Your Constitution score increases by 15