Best definition
City in the world of Lone Wolf. It is ancient, and is buried underground, beneath the modern city of

Tahou. It can only be accessed through the Tahou Cauldron.
The abandoned city-scape of Zaaryx is home to the Zaaryx Ghouls, fearsome creatures which prey on humans, and also the mysterious but good Crocaryx, and strange monsters such as the Zadragon. It is the site of one of the Lorestones.
It attracts treasure-hunters, but few come back alive.

Was the city always home to the Crocaryx, or did it originally have a human population who later became the ghouls? Who knows?