Berzerker

At 5th barbarian level, while raging you can lose 1 turn of rage to gain an extra attack. You can do so once per round. Additionally, the refresh duration of rage(when you kill a creature or are critically hit) is increased by 1.

At 6th level, choose one ability:

• Eye for an eye - When you fail to block damage from a melee attack, you can choose to treat it as a critical strike and make an attack against the creature as a free action. You can do so once per turn.

• Mad rage - Gain resistance to psychic damage while raging, and increase both the initial and refresh duration of rage by 1 turn. 

• Channel fury - You can choose to sacrifice up to as many turns of rage as your constitution bonus as an action to gain a battle dice worth of temporary health per turn of rage spent. This temporary health lasts for 10 minutes

• Mushroom brew - You can spend 1 rest dice during a short rest to prepare 1d2 doses of a frenzy potion, which can be consumed as a bonus action, requires a DC 14 constitution save, and grants 1d3+1 turns of rage on a success, identical to your rage ability, granting any associated abilities you have. A frenzy potion becomes inert after a long rest.

• Brawling - Your unarmed strikes deal an additional 1d6 bludgeoning damage. When using frenzy, you can make 1 unarmed strike as a free action.

• War taunt - You can spend an action to perform a war taunt. All enemies that hear the taunt must make a wisdom save. On a failure, they are all marked for the rest of combat. A marked enemy receives an additional battle dice worth of damage on the first instance of damage they take from you or an ally within 30 feet for the rest of this encounter.

At 7th level, you can spend 1 rest dice during a rest to take 1d6 fire damage that cannot be healed until long rest to cause your rage to grant you regeneration 1, healing you for 1 health at the start of every turn. This effect lasts until the next short rest.

At 8th level, choose one ability:

• Painless - Once per rest during rage, ignore an instance of incoming damage.

• Warlord - You can enter rage an additional time per combat, and you regain 1 battle dice when entering rage.

• Scourge - You can spend battle dice to gain the dice as a bonus to an intimidation check, or an intimidation based DC. +1 Battle dice 

• Beast - You can spend battle dice to gain the dice as a bonus to animal handling checks, or the DC of an ability targeting a beast. +1 Battle dice.

• Juggernaut - You gain medium armor proficiency. If already proficient, gain heavy armor proficiency. If already proficient with heavy armor, gain +1 block from armor.