Barbarians are the purest form of combatant, relying on their strength of body and will to power through all challengers. They eschew the comforts and luxuries of civilization in favor of their most primal attributes and instincts; their armor is their hide, their weapon is anything within reach and their motivation is continued existence. Nothing is more dangerous than a cornered predator, and a barbarian always fights as though that were the case.
Strength is vital for damage-focused barbarians, but it becomes less important if they are dual-wielding or using finesse weapons. It is also helpful for saving throws or for commonly associated skill checks (such as athletics).
Dexterity is important for unarmored or lightly armored barbarians for the extra AC, or for barbarians who are dual-wielding or using finesse weapons. It is also helpful for saving throws.
Constitution is important for unarmored barbarians for the extra AC, or for barbarians for the extra HP. It is also helpful for saving throws.
Intelligence is not important for barbarians, but it can be helpful for saving throws or for commonly associated skill checks (such as nature).
Wisdom is not important for barbarians, but it can be helpful for saving throws or for commonly associated skill checks (such as perception or survival).
Charisma is not important for barbarians, but it can be helpful for saving throws or for commonly associated skill checks (such as intimidation).
While you are not wearing any armor, your Armor Class equals 10 + your Dexterity modifier + your Constitution modifier. (You can use a shield and still gain this benefit.)
In battle, you fight with primal ferocity. On your turn, you can enter a rage as a Bonus Action. Rage lasts for 3 rounds, then you are unable to rage again until you perform a short rest. (At 3rd level, you may rage twice before taking a short rest. At 6th level, you may rage three times before taking a short rest. At 9th level, you may rage four times before taking a short rest.) Your rage ends early if you are knocked unconscious, haven't attacked a creature with a Melee Attack Action or Ranged Attack Action, or taken damage since your last turn. You can also end your rage as a Bonus Action. While raging, you gain the following benefits if you aren't wearing heavy armor:
You have advantage on Strength checks and Strength saving throws.
When you make a Melee Attack, you gain a +2 bonus to the damage roll.
You have resistance to physical damage.
Starting at 2nd level, you can throw aside all concern for defense to attack with fierce desperation. When you make your first attack on your turn, you can decide to attack recklessly. Doing so gives you advantage on Melee Attack rolls during this turn, but attack rolls against you have advantage until your next turn.
At 2nd level, you gain an uncanny sense of when things nearby aren't as they should be, giving you an edge when you dodge away from danger. You have advantage on Dexterity saving throws against effects that you can see, such as traps and spells. To gain this benefit, you can’t be blinded, deafened, or incapacitated.
Starting at 3rd level, you can go into a frenzy when you rage. If you do so, for the duration of your rage you can make a single Melee Attack as a Bonus Action. When your rage ends, you suffer 1d4 damage.
Beginning at 5th level, you can attack twice, instead of once, whenever you take the Unarmed Attack or Melee Attack Action on your turn. You may replace either of these attacks with a Grapple or Shield Bash action (if a shield is equipped.)
Starting at 5th level, you may take a Disengage Action as a Bonus Action.
Beginning at 6th level, you can't be charmed or frightened while raging.
By 7th level, your instincts are so honed that you have advantage on initiative rolls.
Beginning at 9th level, you roll one additional damage die when dealing extra damage for a critical hit with a Melee Attack.
Beginning at 10th level, you can use your Standard Action to frighten someone with your menacing presence. When you do so, choose one creature that you can see within 20 meters of you.
If the creature is not Blind or Incapacitated, it must succeed on a Wisdom saving throw (DC equal to 8 + your proficiency bonus + your intimidation) or be frightened of you until the end of your next turn. This effect may end early if the creature ends its turn out of line of sight (or becomes Blind or Incapacitated), the combat ends or the creature Flees combat. (Important: the creature is not forced to attempt to Flee.)
On subsequent turns, you may choose to use your Bonus Action to extend the duration of this effect on the frightened creature until the end of your next turn. They re-attempt their Wisdom saving throw and if the creature succeeds on its saving throw, you can't use this feature on that creature again for 24 hours. If the creature fails, the above effect is reapplied.