Environment Design - Personal Project

Working on some ideas for a personal project. Don't have a name yet for it, but the setting is in a dark fantasy kind of world. The idea behind this piece is that, that monolith as many more scattered around the region and locks for a prison that holds an evil entity. Over the millennia, and due to the rough weather in the region, the power of those locks has waned and that evil presence has begun to spread its corruption through the land.