What Kerwyn sees at the bottom of the cavern...
On what appears to be the true bottom of the collossal cavern, the stone is worked and smooth. Two symbols are carved into the floor on the western side of the cave: A two-tiered inverted ziggurat, black in color, and a flaming sun, also jet black. Rising from the middle of the cave, a pillar supports the black and violet mass of the enormous obelisk on whose surface you recently stood. On the other side of the cave, water spilling from above collects into a pool.
D/E. The black inverted ziggurat and black flaming sun symbols engraved on the floor of the cavern almost seems like the protective circles that Kerwyn studied in school, except strange. The black sun in particular seems an evil perversion of the otherwise good solar sign of light and life.
F. Impossible though it seems, the huge obelisk comes to a very narrow point that is balanced atop this 30 foot high stone pillar. The pillar has been carved from the rock itself and appears to be quite solid. Iron rungs, mostly free of corrosion, have been ahmmered into it, allowing anyone to climb to the point where pillar meets obelisk.
G. An archway is carved out of the stone cavern in such a way that it seems to be nothing but a curved mass of writhing tentacles and serpents. Beyond the opening is a smooth black wall.
H. The water that pours down from above, spattering across the top of the obelisk, finally collects in a pool at the bottom of the cavern. About 10 feet across and perhaps 2 inches deep, it fills an imperfection in the floor's otherwise smooth surface. The water runs in a rivulet across the floor through a large crack in the cave wall, disappearing into the earth.