Netherlight Prison

Publisher's blurb:

A purple light flickers in the distance towards the end of the winding stone tunnel where a wall has collapsed. The main door has been barred by the fallen debris but the collapsed wall luckily gives access to a ledge and balcony above violet abyss.

After turning a corner you find yourself in a large room that has partially collapsed, the floor is lined by large metal grates and below them a stream of viscous purple liquid flows out towards the edge of the abyss. At the far end of the room there are multiple pillars between which solid iron poles create some type of jailed area. Within this area is an intact crescent basin of sorts, full of the strange purple liquid and strange glowing runes carved into the ground.