I'd imagine something like a fantasy version of a military drummer or bugler. Background - an adult who feels their duty is to join combat but perhaps is not as proficient at fighting as others, and his proficiency at music has led him to be made into the savage bard of a group of barbarians. Alternatively, a child, perhaps an orphan of someone who used to serve in the barbarian band that he's now part of.

The role of the Savage Bard... the leader of a group of barbarians could use the various tunes of the savage bard to communicate with his troop across the battlefield to coordinate tactics and communicate battle formations. The bard might also be required to use their music to give some magical support to the group.