The music and sound design in Zerith Mortis is really well done. I think everyone on the team deserves some praise! Halondrus sounds cool and the raid in general has an interesting and motivating soundtrack.
In general the music has a beautiful film-like quality and creates imagery that is congruent to the visual design.
There are a few of the songs in the general Zerith Mortis area that are really quite good objectively, not just in the game in my opinion. I think my favorite is in the Catalyst Gardens