If you want to explore the vastness of Metropolis, the chambers of Inferno, the desolated realms of the Underworld my recommendation is that you listen to Atrium Carceri. Dark Ambient music that reaches true spiritual depths.
The genius behind the music, that takes your soul on journey, is Simon Heath. From the excellent interview that can be found here we learn that he has an insight in the world of KULT: Divinity Lost and gnosticism in general.
– The ancient city, where humanity once ruled as gods before being banished to our reality. This mirage will sometimes break down in single individuals, and the interference usually takes the shape of themes from my early material; trauma, schizophrenia, psychosis and depression.
These dark hymns are perfect to get you and your players in the right state of mind and breathes KULT. Below is a small sample from his upcoming album. The art is a depiction of Metropolis if you ask me.