Path of the Whirlwind

Path of the Whirlwind barbarians care not for collateral damage, they are a walking tempest on the battlefield, laying waste to all in their path with a weapon in each hand.

Wanton Violence

Starting when you choose this path at 3rd level, you double your Barbarian Rage Damage Bonus on targets you haven't previously damaged with an attack this turn.  If you deal this extra damage more than once on a turn, you also gain temporary hit points equal to your proficiency bonus.

Bloodlust

When you reach 6th level, when you take an Opportunity Attack, you may also move up to 10 feet as part of the same action.  If your attack deals damage, the target's movement speed is halved until the end of their turn.

Into the Fray

Also at 3rd level, when you Rage as a bonus action, you can attack with your off-hand weapon as part of the same action.

Force of Nature

Your movement speed can no longer be reduced by mundane or magical means, and you have advantage against being frightened or immediately incapacitated while raging.

Collateral Damage

Once at 14th level, you become an unpredictable whirlwind of carnage.  Whenever an enemy targets you with an Opportunity Attack, or ends its turn within 5 feet of you, you can force it to take damage equal to your Strength modifier.  This damage is the same type as one weapon you are wielding.