Path of the Stormwielder

 Wind, Rain and Thunder. The Storm is the quintessential force of nature, comparable only to volcanoes and earth- quakes. A Barbarian can tune in with such a force by manifesting the will to become unstoppable and inescapable. This bond is not without risk: once summoned, the Storm can only grow until it discharges its immense power on something or someone. Such as you.

This is the subclass made by Mana Project studio, I changed a few things to give dragonborns a godzilla feel. Lemme know what you think!

Storm Caller

You can hold up to a number of Storm Charges equal to your barbarian level .

Every time you have a number of Storm Charges equal to your level,or when your Barbarian Rage ends, you immediately lose all charges and receive 1d6 points of damage as the unbridled storm surges through your body. This damage cannot be prevented in any way.

Thunder Blow

Starting at 3rd level, you can channel the might of a gale-force-wind. When you use the Attack action while raging, you can empower your weapon to deal an extra 1d6 thunder damage with each successful attack. You gain one Storm Charge for each attack empowered this way, two charges on a critical hit.

Thunder Blow feature increases when you reach certain levels in this class, increasing to 1d8 at 6th level, 1d10 at 10th level, and 1d12 at 14th level

Thunder Blow also applies to a Dragonborns Breath Weapon ability 

Calamity Rod

Starting 3rd level, you can discharge the storm on another living creature. As an action, while you are raging, make a single melee weapon attack against a creature. If it hits, the target and all other creatures within 5 ft. of him suffer 1 thunder damage for every Storm Charge you possess and you lose all of your Storm Charges.

 If the attack fails, you gain a number of Storm Charges equal to your Rage Damage.

 Starting at 10th level the area of effect of your Calamity Rod feature increases to 10 ft

Calamity Rod also applies to a Dragonborns Breath Weapon ability 

Unleash The Gale

Starting at 6th Level, you have advantage on saving throws made to resist being moved, pushed or knocked prone. Also, when you’re hit by a melee attack, you can unleash a sudden wind, causing 1d6 thunder damage to the attacker and gaining a Storm Charge.

Unleash the Gale damage increases when you reach certain levels in this class, increasing to 1d8 at 10th level, 1d10 at 14th level, and 1d12 at 20th level.

Imbue The Cloud

Starting at 6th level you can fill your weapon with the essence of a rumbling blizzard cloud. When you activate your Thunder Blow feature, you can convert all the weapon damage (whether slashing, piercing or bludgeoning) into lightning or cold damage. This feature also converts any extra damage, including your Strength or Dexterity bonus.

 Every time you make an attack with Imbue the Cloud, you gain a Storm Charge, in addition to the one gained from Thunder Blow.

One With The Winds

Starting at 10th level , you can cast Control Weather as a ritual.

If you use Control Weather to summon Rain, every enemy within your summoned Rain will take double damage from your lightning related abilities in this subclass

This does not apply to natural Rain or another Spellcasters Control Weather spell. This applies to the Barbarian that cast Control Weather with this Subclass feature.

If you are a Blue or Bronze Dragonborn, your Breath Weapon damage also doubles in your Summoned Rain

Step Of Thunder

Starting at 14th level, as a bonus action, you can cause a halo of lightning to surround you until the end of your turn, gaining 5 Storm Charges. When you do, each creature with 5 ft of you must make a Dexterity saving throw.

On a failed save, the creature takes 5d6 lightning damage.

On a successful save, the creature takes half as much damage. The DC is 8 + your proficiency bonus + your Constitution modifier.