the underground prison in the fantasy world is a vertical deep well prison carved into black basalt. the four walls are lined with honeycomb-shaped stone cells, each cell featuring rusty bronze bars. in the center of the bottom of the well, there is a circular stone platform suspended by chains. the surface of the stone platform is engraved with dark sealing patterns. the grooves on the four walls are flowing with dark blue soul flames, which are the only source of light, stretching shadows extremely long and distorted. there are floating ashes and a thin layer of corrosive green toxic fog in the air. the overall environment is almost completely black, with high contrast between light and dark, creating a depressing and suffocating atmosphere. it has a cinematic mid-shot, a cold and composed composition, volumetric toxic fog columns, 8k ultra-fine resolution, and an eastern fantasy realistic style.