The opening riff starts at 0:10. The root note is obviously the note B, and you can also see the minor 3rd in bar 2. There are a few chromatic passages too, and the riff ends with a C power chord at the end of bar 4. So you may see it as a B phrygian riff, but if you look at it closely you’ll see that the C note, which would represent the minor 2nd of the phrygian mode, does not play a significant role. So this riff is not about the phrygian mode. The “pseudo-phrygian” vibe at the end of a riff is a common trick in prog metal. So I’d rather call this riff a B minor pentatonic rock/blues with chromatic notes.
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