I just wanna help you with your TCO Campaign with the Music List ^_^
This is a song from Avenged Sevenfold - Save Me and it has an epic intro, maybe this intro is good to be put in a boss fight, perhaps ?
Intro: 00:00 ~ 02:00
Boss-fight-like-sound: 00:53 ~ 01:08 (but this is too short lol >.<")
But you can hear the full song of it, length about 11 minutes, that's the time to kill a boss ! Isn't it ?
Good Luck with your project !
And, please inform me if your choose this music to be the music in that campaign !