Path of the Raiu Barbarian

Your Rage taps into the power of thunder storms.  Raiu is Japanese for Thunder Storm. 

Lightning Stike

  “Lightning Strike”  While your Rage is active, when you take the Attack action on your turn, you can make your attacks and call down a bolt of non-magical Lightning on any target within 60 feet of you.  The creature must make a Dexterity saving throw.  On a failed save, a creature takes 2d8 Lightning or Thunder damage (your choice) or half as much on a save.  The DC is 8 plus your Strength modifier and Proficiency Bonus.  At 9th level Barbarin, the damage increases to 3d8 and it becomes 4d8 at level 16 Barbarian. 

~ Doing extra Lightning Damage to a single target ~ 

Channel Lightning

  “Channel Lightning”  While your Rage is active, when you take the Attack action on your turn, you can replace one of your attacks with a beam of non-magical Lightning.  This beam of lightning is a 30-foot Line that is 5 feet wide.  Each creature in that area must make a Dexterity saving throw.  On a failed save, a creature takes 3d8 Lightning or Thunder damage (your choice) or half as much on a save.  The DC is 8 plus your Strength modifier and Proficiency Bonus.  At 6th level Barbarin, the damage increases to 4d8 and it increases by 1d8 every 3 levels of Barbarian gained after that.  

~ Does Lightning Damage in a small AoE ~

Invigorating Shock

You have resistance to Lightning and Thunder damage.  While your Rage is active, whenever you take Lightning or Thunder Damage, you gain Temporary Hit Points equal to twice the amount of Hit Points and/or Temporary Hit Points that you lost. 

Lightning Strikes Twice

  “Lightning Strikes Twice”  While your Rage is active, when you take the Attack action on your turn, you can make your attacks and now call down TWO bolts of Lightning on any target within 60 feet of you.  In addition, any Lightning or Thunder damage that you deal ignores Resistance and all immunity to Lightning or Thunder damage is treated as Resistance instead. 

~ Boosting Damage for Tier 3 and 4 ~ 

Blinding Flash

 If a creature takes Lightning damage after it fails any saving throw that you force, it is now blinded until the end of your next turn.  If a creature takes Thunder damage after it fails any saving throw that you force, it is knocked prone.