Phantom Palace is a music theme featured in Castlevania: Aria of Sorrow. It is the background theme that plays in the Inner Quarters area in Dracula's vacant castle.
A remixed arrangement of the theme called Phantom Palace Fontaine is later featured in its original soundtrack.
Let's Listen Castlevania Aria Of Sorrow - Inner Quarters (Extended)
Castlevania Aria of Sorrow - Phantom Palace Fontaine