This is a remix of the King of Sorrow's theme, but with pieces of Kingdom of Sadness and Going to Lunatea.
Never has a theme fit a character so well. Normally I dislike vocals I can't understand, but the singer here makes the song complete.
By the way, I thought I'd add that this whole album was ripped by BigCN. So if I ever come across him, I owe him some gratitude.