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.
Use Berserker skills."Help" description
Savagery is the command skillset for the Berserker class.
Rage is the job level 14 ability for the Dark Knight. It repeats Dark Bane on a random enemy target until HP is 1, or up to 5 times. It costs 2 BP to use.
Bravely Second: End Layer
Rage is the job level 10 command ability for the Dark Knight. It allows the user to unleash Dark Bane against random targets up to five times, or until their HP falls to 1. It costs 2 BP to use.
Rage (often called fury or frenzy) is a feeling of intense, violent, or growing anger. It is associated with the fight-or-flight response and often activated in response to an external cue, such as an event that impacts negatively on the person.