The Feldip Hills

Far to the South-Western reaches of Siridia lies the Feldip Hills, a highly caustic spanse of marshland, a never ending acid rain, and toxic lakes. Few venture down into the Feldip Hills nowadays as it requires extensive amounts of additional protective gear to shield the body from the caustic atmosphere. A standard humanoid creature without additional protective measures in place will die within 4 hours of simply breathing the air here.
The Feldip Hills were not always a caustic cesspool though, it became this way due to the events of The God Wars. The effects The God Wars had on the area are only second to Forinthry. Some creatures have adapted to the new atmosphere and those that thrive are considered some of the most dangerous creatures within Siridia. One particular race that has taken a strange adaptation to the region are the "Jiggig Ogres". They are a race of highly intelligent ogres who's natural form has heavily mutated over the ages. They're ancestors constructed a Citadel to Basilikos called Gu'Tanoth and is the central hub for the Jiggig now, and are one of the few only known races within The Feldip Hills to possess any level of notable intelligence. The Jiggig completely dominate the entire region, but thankfully have never ventured far out of the Feldip Hills over the ages, and are generally not considered an active threat to bordering settlements.
During the God Wars, Gu'Tanoth was created as the central fortress to Basilikos, from which he commanded his armies from. Only some relics and tools of Basilikos can still be found to this day while venturing through the Feldip Hills- as many of them are believed to have been recovered by the Jiggig. Researchers have suggested that the nature of the Jiggig and their ability to survive and adapt may be due to the effects of some of these relics that they have under their control.