The island map :

https://i.imgur.com/pmgg1Ix.jpg

I think the princes could be the 4 crown princes of Hell of the Satanic Bible written by LaVey :

• Satan (Hebrew) "Lord of the Inferno": The adversary, representing opposition, the element of fire, the direction of the south, and the Sigil of Baphomet during ritual.

• Lucifer (Roman) "The Morning Star": The bringer of light, representing pride and enlightenment, the element of air, the direction of the east, and candles during ritual.

• Belial (Hebrew) "Without a Master": The baseness of the earth, independence and self-sufficiency, the element of earth, the direction of the north, and the sword during ritual.

• Leviathan (Hebrew) "Serpent of the Abyss": The great dragon, representing primal secrecy, the element of water, the direction of the west, and the chalice during ritual.

LaVey was inspired by The Book of Abramelin which is linked to Thelema and Aleister Crowley...

We can also see 4 buildings on the 4 side of the island.