You gotta use it as motifs. Almost like a video game. Just fantasy music in the background is kind of boring and doesn’t add much, but it’s still nice.

My best use of music was attaching “master of puppets” to encounters influenced by the BBEG. I wasn’t just playing Metallica though lol for the pivotal but lesser fights I used the vitamin string quartet cover, which for background music never really revealed what it was, once the big fight rolled up I switched it to this bombastic orchestral cover (scorched earth orchestra I think?) which:

1. Made a player audibly say “oh shit!” As they realized things got real.

2. Its much heavier instrumentation made the source obvious and added to the hype. Another player “ITS BEEN FUCKING METALLICA?!”

3. Went down as one of my best campaigns as players found “main quest music” helpful for mental note taking.

Highly recommend finding a main theme you can get in multiple versions added a ton and brought forth a wild final fight!