Just a crazy idea:
Music in Yliakum was lost centuries ago because ever since Laanx was in exile the people found no reason to ever make music again because nothing could ever help her torment. As time went on music was lost and is now only a forgotten myth. During that time instruments were lost and became lost artifacts, and the notes on music scores were never used so the spirits of each individual music note drifted away into the hearts of all the creatures hoping that they\'ll never be forgotten.
But there was one man who didn\'t forget, he was a blacksmith who created instruments and he was the only man who knew about music. He has the blueprints on how to make music and knows how to play all the instruments in Yliakum, except he has yet to be seen or found.
Since there will be music playing (we assume) it\'s a good idea that music should play an important role in battle. Each type of instrument should have a different status effect. I don\'t believe music should damage the enemy but cause negative status effects to the monster or positive status effect to yourself or a team.
How music is learned:
This is the way I see it. If you take my idea about music notes going into the hearts of people, I didn\'t say specifically just player characters. It could also be in monsters. I think there should be different musical note spirits, each one a different sound. These musical note spirits should be items that can be acquired through monsters. When you acquire a musical note spirit that specific note should be learned. Because in my story above, if music was forgotten then it has to be learned all over again. Also there could be a few musical spirit notes that are flying like fairies around and to catch it you need a special bottle that you can get by the old man that knows everything about music, as stated above.
As for instruments I don\'t really care what they are but i think that all instruments should have positive effects and negative effects. For example:
A trumpet can cure HP and can also blind an enemy. The trumpet should be used for blinding the enemy but it won\'t cure HP as much.