Somewhere in these crypts, there is still the undead remnants an adventurer-archaeologist searching for the obvious secret door into the central circle.
The crypts of the Ophidian Emperor were built around a double-circle motif, designed to feel like a snake curling around the tombs and crypts. To further accent the motif, the circular halls are set about three feet lower than the other chambers and crypts. The various chambers are tombs, crypts, and βtreasure roomsβ stacked with fake grave goods to accompany the Ophidian Emperor into the afterlife.

All doors within the crypts are fairly thin single-piece stone blocks mounted on metal hinges. All doors and most walls are decorated with frescoes and bas-relief carvings of idealized images of the reign of the Ophidian Emperor, often showing off his mighty golden snake staff and the black Orb of Empire.
https://rpgcharacters.wordpress.com/2018/10/08/circle-crypts-of-the-ophidian-emperor/