Scriabin was an odd (quite possibly insane) guy, but he was also probably a fucking genius. he believed in theosophy and mysticism, had synaethesia (saw sound as color), and believed that his music could bring about the end of the world (riiiight). but dude went hard - his method of piano playing at Moscow Conservatory was so brutal that he lost the use of his right hand!! so his 1st sonata is a brilliant emotional response to that, albeit a straight up late-Romantic one... although you can hear a lot of dom7th chords with added 9-11-13ths stacked on top, basically pre-jazz voicings. but around sonata #5 ('Poem of Ecstasy'), shit really starts to get weird. he wanted the harmonies to be brighter, so those 7th chords start to stretch, as notes are #'ed and the intervals move from 3rds to 4ths. we're talking the birth of atonality here, well before/independent of Schoenberg, and coming from purely organic and sound-based ideas - no math, no vectors. his minor 9th-based "Black Mass" (#9) is probably the archetype for this style of writing, but don't overlook #10's shimmering trills or the showstopping 2 Dances, op. 73 (his club banger). i really love to hear an artist's craft evolve over the course of their career, and for my money few composers have as steep a trajectory as Scriabin.
"I Am God"