Sorry for the delayed review. I've been working.

I really like the ideas found here. I would really try to build some different chord progressions to add some variety and pique more interest. While it was interesting in the beginning where it bellowed up, it got a little tiresome after some time. The trumpet melodies were very nice though. I would try to build some more harmonies using violins. You did use an oboe (or at least what I perceive to be an oboe), but I think the parts could be made even more exciting.

Some tempo variations could help give the idea of a story progression as well. I really wanted it to speed up, but it didn't happen.

Now for the good: the melodies were quite interesting. I liked the stark contrast between the royal sounding trumpet, majestic in nature, with the dark, almost overpowering strings. Nice job on creating the mood. Since this is a stand alone, some sound effects could also come in nicely.

Now don't take my word for everything, since I'm not expert myself. That's just my two cents.

Evil

Kind of reminds me of Sephiroth from Final Fantasy VII actually. This does sound like a very dark and evil theme though so that worked out well anyways. Nice effects and all since it makes it all sound darker.

The trumpets have a very dark sound to them so that works out well with a piece like this in my opinion so nice working on it. The harp when it comes is very light and sinister actually. The bass like sound is also very cool here. It just makes it sound darker.

I think this would work as a pre boss battle theme as you did a nice job working on this one.

Overall ,creative and very dark feeling.