To me, the really intimidating part of Solas’ theme song is that the game introduces it so slowly - first you only hear these thrumming, oppressive war drums (and you didn’t know why - why are there drums? Why??). When you fight the Saarebas, strings come in to lead the drums.
Only when you start fighting the last boss of the game, do you finally hear Solas’ real, complete theme song. Something like a metaphor for hunting down the pieces to the mystery behind the character himself.
I put the three versions of the song together to make a version where one builds up into the next, the way it does in the game. 6-minute panic attack.