Rage (ability)

Rage, also known as Riot, Instinct, and Savagery is a recurring ability and skillset in the series, often used by the Berserker class.

Final Fantasy VI
Rage is the command ability for Gau, which allows him to copy a monster's stats, elemental and status resistances, innate abilities, and a couple abilities, but places Gau under a Berserk-like state until he dies.

Rage is also an enemy ability used by Devoahan and Aspidochelon which deals moderate non-elemental physical damage to one target.

Final Fantasy X-2
Instinct is the command skillset for the Berserker class.

Final Fantasy Tactics A2: Grimoire of the Rift
Savagery is the command skillset for the Berserker class.

Etymology
(often called fury or frenzy) is a feeling of intense, violent, or growing anger. It is associated with the and often activated in response to an external cue, such as an event that impacts negatively on the person.