i had to split my boss music in two for it to fit on the newgrounds servers.
monologue + truncated boss theme (essentially, the music that plays immediately after the monologue parts stop).
i believe the final boss needs music that envelops as many themes from the game itself, or those associated with the character(s). this is no exception, but is still a little different in that there haven't been any other themes written for this "game". what i've done is imagined themes that might have been in the idea at some point and weaved them in and out. even the simple piano-ish part is from another idea i had when constructing another song. the actual battle picks up the pace after this.