It typically lasts 8–10 minutes, and is marked as follows: Like Scriabin's other late works, the piece is highly chromatic.
The Black Mass Sonata is particularly dissonant because many of its themes are based around an interval of a minor ninth, one of the most unstable sounds.
Its marking 'legendaire' exactly captures the sense of distant mysterious wailing which grows in force and menace.
[1] The opening theme is constantly transformed, from the early trill arpeggio's sounding unsettling and then completely shifting, eventually tumbling in rapid cascades into a grotesque march.
[1] Scriabin builds a continuous structure of mounting complexity and tension, and pursues the combination of themes with unusual tenacity, eventually reaching a climax as harsh as anything in his music.