Viking Beserker

Many can claim to be a barbarian, to throw back their heads and howl and they charge head long into their enemies, but few have worn the bear skin, have drank the draught of red rage.  Weather its the drink of rage, the sight of hated foes,  or just the love of the destruction they're about to bring to the field, these terrifying warrior's battle rage goes beyond reckless abandon, theirs is the realm of truely mindless fury.  Some use the bear shirt, some consume an elixir that fogs the mind of all but their fury,  others work themselves into the state through chants and oaths to the Gods.  Their cries to these Gods are barely understandable through the foam and inhuman roars and bellows they now produce.   Covered in tattooed runes, and countless scars,  the Beserker's fearsome presence, even while feasting and celebrating, unnerves some onlookers.  Where others who feel the rage will still wear what armor they can, the Viking Berserker throws off even the lightest armor when the maddening battle lust is upon them, armored only in their madness and the will of the All Father.   When the battle ebbs, and the battle madness subsides the nicks and scratches left on the warriors body, a sign of his victory open up to flow, now a price he pays for living to fight again.  

Madness of the Bear Skin

Starting when you choose this path at 3rd level,  if wearing no armor, and not carrying a shield, you go into the Madness when you Rage.   While in the Madness you cannot be frightened or charmed.  You can also make a single melee attack as a bonus action on each of your turns.   If you are not in melee when the Madness begins you may take a dash action to run to the nearest enemy.  When the Madness ends, you suffer one level of exhaustion, and if you received any slashing, piercing or bludgeoning damage while in the Madness you will suffer 1d6 minus your Con Modifier of unavoidable damage.

Favored of the Gods

At 6th before you enter the Madness you can chant to a God that they might watch your destruction, and that it might entertain them, and maybe they'll grant a boon in return.

Beginning at level 6 before entering the Madness choose which God you will chant to, that God if willing will grant the following bonus during the Madness:

Favor of Odin:  Temporary hit points equal to your level plus Con modifier, however, after the end of the Madness you incur the full 6d unavoidable damage, cannot sub track Con Mod from damage.

Favor of Freya:  You have advantage on the first round of attack(s) made after entering the Madness.

Favor of Thor:  Any creature you successfully crit must make a strength check DC 8 plus your strength or athletic score plus your charisma modifier or be knocked prone.

Favor of Hel:  Damage you deal to a creature cannot be healed unless the creature succeeds a constitution check DC 8 plus damage done plus charisma modifier

Favor of Loki:  You may use your reaction to attack any creature that misses a melee attack on you, this attack cannot be a critical.

Battle Terror

At 10th level you have an aura of intimidation.  By either your fearsome reputation, or by your visible blood lust, you cause your foes to cower in fear.   While in the Madness enemies within 15 feet of you must pass  a Wisdom saving throw (DC equal to 8 + your proficiency bonus + your Strength mod) or take disadvantage on attack rolls while within this area.  Enemies immune to fear are immune to this effect.  

If the enemy passes its saving throw, it is immune to the aura for 24 hours.

Valhalla Awaits

Beginning at level 14 if your hit points are reduced to 0 while in the Madness you will not become unconscious, instead you will gain half your level plus Con modifier temp hit points.  Once the Madness ends, the temp hit points are removed, and any consequences of reaching 0 hit points are applied as normal.   While in this state retaliation also applies, and you may use your reaction to make a melee attack against any creature that does damage to you, however you may not take a movement to reach the target creature.