In that game's story, they're a small group of badass military-trained archers reviving an ancient practice of song magic for combat use, in an era where the term Bard is more commonly associated with tavern peddlers whose songs hold no power today. But past Bards once held sway over the people, as their songs were tempered by their experiences in combat.
The allied military is totally unconvinced about the value of these songs in a military setting at first, but you and one other bard along with a higher ranking commander manage to convince them to allow you all to go on an expedition to search for an ancient supposedly destructive song that may be useful against the enemy Empire. The group eventually expands their search into a place that few mortals had ever stepped in for the past thousand years (IIRC the only other job quest arc that touches that region is Dark Knight), and the local dragons and moogles direct your search towards another mysterious set of islands floating in the skies. But it turns out that the song was in reality a sealed Siren that basically wiped out an entire moogle colony in the distant past, so you kick her ass after accidentally unsealing her, and the group returns to the military empty handed. But the group manages to convince the leaders that the entire trip was worth it anyway and that they ended up way stronger as a result, so the leadership decides to let your group establish an entire new experimental platoon of bards in the military.
Then the group is given their first assignment shortly after, but you haven't actually recruited anyone yet, so it's just you, the other bard, and the high ranking commander still. At the time, the allied military as a whole is trying to liberate a nation that had been taken over by the enemy Empire, but said region had previously gone to war with the allied forces 50 years prior to the start of the game. A commander from the allied military had been assassinated during peace talks towards the end of that conflict, and for some reason the military chose to cover that up at the time. Their grandson uses your group to find an old journal explaining everything, with the intention of exposing the cover-up in order to cause public opinion to turn against assisting in the liberation of the region. You manage to keep the journal when said grandson and a group of his allies attempts to take it from you, but the commander gets kidnapped later while assisting with a different task, with a demand to exchange his life for the journal.
So you go back to the leadership trying to get support, yet the higher ranking leadership decides that they don't want to negotiate. You and the other bard then decide 'to hell with that noise' and start making plans to go rescue the commander yourselves, but the military commander relaying the information then reveals that he already planned to join your unsanctioned rescue attempt, and has already recruited the mentors of the local lancer and archer's guilds to help. The group of 5 then goes out to kick ass and rescue the kidnapped commander. At this point though, your group decides that they shouldn't be assisting in the coverup either, and that they are under no obligation to just surrender the journal back to the alliance leadership since they didn't officially help with the rescue. So the commander manages to successfully argue that the group will only surrender the journal if they are allowed to reveal the truth to the public at a later time in the future, long after the region in question is liberated.
In the game's present story, the platoon of Bards finally has recruits and they even take to the field in battle, but certain unrelated story events took your character out of the picture for that, and the recruits were said to not have been able to perform as they should. Upon your return, you're asked to directly train them. Though the training mostly consists of taking the recruits to where you killed the Siren from before and singing an inspirational song. Weird flex, but okay.
