Avernus creates environmental strife
Artistic creation
5100BBE
Avernus is said to create disease, plague, and other sorts of enviromental strife. All this is to test the denizens of Evandyr and make them stronger. Suffering begets strength.
In truth, as erosion is of Stygia, storms are of Medicopia, rot is of Narhiim, and plague is of Limoseht, it is widely theorized that Avernus did not "create" this sin, but rather form convocations and pacts with extra-dimensional powers to invite such foreign powers to grow within Sartova.