In terms of chords and melody, Fi's Theme is more complex than the typical song, having above average scores in Chord Complexity, Melodic Complexity, Chord-Melody Tension and Chord Progression Novelty.
Fi's Theme is written in the key of E♭ Dorian. According to the Theorytab database, it is the 8th most popular key among Dorian keys and the 40th most popular among all keys. The E♭ Dorian scale is similar to the E♭ Minor scale except that its 6th note is a half step higher (C). Chord progressions in Dorian have a characteristic sound due to the major quality of the chord built on the 4th scale degree. See the E♭ Dorian Cheat Sheet for popular chords, chord progressions, downloadable midi files and more!