In terms of chords and melody, Guardians - Illusion of Gaia is significantly more complex than the typical song, having above average scores in Chord Complexity, Melodic Complexity, Chord-Melody Tension, Chord Progression Novelty and Chord-Bass Melody.
Guardians - Illusion of Gaia is written in the key of D♯ Locrian. According to the Theorytab database, it is the 4th most popular key among Locrian keys and the 76th most popular among all keys. The D♯ Locrian scale is similar to the D♯ Minor scale except that both the 2nd and the 5th notes (E and A) are a half step lower. This means that the characteristic "home base" chord of D♯ Locrian has a dissonant diminished quality (d#˚), which makes it a very uncommon choice for songs. See the D♯ Locrian Cheat Sheet for popular chords, chord progressions, downloadable midi files and more!