Music by Kevin MacLeod (based on Chopin). Available under the Creative Commons Attribution 3.0 Unported license. Download link: https://incompetech.com/music/royalty-free/index.html?isrc=USUAN1100657

MacLeod's description:

Genre: Horror
Length: 3:23
Instruments: Percussion, Piano, Choir, Orchestra, Pipe Organ
Tempo: 77

Epic piece taking off from Chopin's famous funeral march (Piano Sonata #2). Death! Death! Death!
ISRC: US-UAN-11-00657
Action, Dark, Epic, Intense, Somber, Unnerving 2009