Tip: If you make a change to your ROM that you regret, just go to File > Restore > Restore ROM to Previous State in the menu. From there, you can select a restore point and revert your ROM to a previous state.
This music plays in the first dungeon of the last special episode: In the Future of Darkness. I revised this port to make the volume sound lower and also adjusted the instruments too to not overlap over others.
This music plays in the Brannoch Castle area in Quest 64. This theme will mostly fit in a final bowser course or an intense level with a dark atmosphere on it, kind of like how Brannoch Castle is in a gloomy region with a purple skybox.