Less of a country and more of a collection of allied city states nowadays, Grehel was for a long time what was left of the Great Liwilai Empire after The Great Wasting; and even before The Great Liwilai Empire, a powerful empire of its own, with territory reaching into Liwilai. For centuries after this, Grehel was, as a unified kingdom, able to keep much of its legacy alive, as well as quite a bit of its knowledge, which was lost to most of the world. Nowadays though, in the aftermath of several invasions and occupations by the Osé Sultanate, Grehel has splintered back into multiple city-states with their own unique cultures, but all under the same banner.
Most people in Grehel worship a unique pantheon of local gods that aren't worshiped anywhere else, whom they call the Olympian Deities, most of which are said to be located on a mountain in the plane of Arborea that also has a counterpart with a gateway to it somewhere in Grehel, though the people in Grehel also acknowledge the other deities of Sancstoryl, but in a much smaller extent than anywhere else.
Outside of the cities and strewn about villages, Grehel is probably one of the most rural places on the continent of Liwilai. There are barely any paths and roads between the different city-states, making travel between them quite dangerous and laborious. However, the ancient ruins that are strewn about often attract adventurers and archeologists.