These barbarians, different as they might be, are defined by their rage: unbridled, unquenchable, and unthinking fury. More than a mere emotion, their anger is the ferocity of a cornered predator, the unrelenting assault of a storm, the churning turmoil of the sea. For some, their rage springs from a communion with fierce animal spirits. Others draw from a roiling reservoir of anger at a world full of pain. For every barbarian, rage is a power that fuels not just a battle frenzy but also uncanny reflexes, resilience, and feats of strength.

https://open5e.com/classes/barbarian.html