Necropolis (Book One). Necropolis, #1

Necropolis is a dark fantasy series about the afterlife in which eight men, three after being killed, and five after entering a portal, acknowledge the life they once knew ended, but continues within the hellish confines of the underworld. Hell is the operative word as this is a story featuring curses, black magic, and the supernatural powers who impose them. Being cast into a lake of fire is one of a number of potential horrors the men face should they fail to avoid the Shetani, malevolent spirits personified as men. These misanthropic and supernatural forces who work in concert with the necromancer, the chief practitioner of dark arts and sorcery, could not be more indifferent to the fallen men's plight.
The man eating ghouls, and the gargoyles they encounter while on their never ending quest to find safety aren't any more hospitable. In the midst of desperation to discover whether there is a way to find some place of refuge or save their souls, five of the eight men learn the Necropolis, a diamond-studded jewel imbued with a magical power, is critical to their having any hope of finding salvation.