Situated in the foothills of the Menador Mountains, Ridwan sits on a hostile volcanic plain. The city is the religious center for the faithful of Zon-Kuthon, as it is said that the Midnight Lord first emerged upon Golarion from the smokey Shadowflame Rift that dominates the city's central square. The rift itself is believed to be a gateway to a particularly unpleasant chasm on the Plane of Shadow known as the Deeping Darkness. Apart from being a religious center, Ridwan is also home to the training camps of Nidal's military,1 who hone their skills to spread the word of Zon-Kuthon through guile or force throughout the world.2
In the year 4200 AR, Kuthonites began construction of a shrine to their master on the Weeping Fields, the place where the chiefs of the local tribes had sworn their eternal vow to the Dark Prince. A settlement grew up around the shrine in the following years, eventually becoming the city of Ridwan.3
Nothing grows on the blasted, volcanic hills and plains surrounding the city, and even water is scarce. All life-sustaining food and drink is brought forth solely by the divine will of the Midnight Lord and his servants. Priests and mages devoted to Zon-Kuthon bring shadowy creatures through the rift at the city's center. After breaking their will, these creatures are then trained to serve Nidal, either domestically or abroad (generally in Cheliax).2
Paizo published an article about Ridwan in Nidal, Land of Shadows.
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