It was the way of the Etturan Dynasty to show the might and connection to the earth of the rulers to dig out underground complexes to serve as tombs. Some tombs were fairly simple affairs, dug down as far as they could manage before the ruler’s death. Others were more massive undertakings – complexes of tombs, crypts, temples and shrines dug into the native stone of the land.
Prince Delan’s Tomb is one of the Etturan Dynasty’s “lost tombs” – roughly 40 tombs who’s locations were lost with the burning of the Tarek Archives. The tomb itself is a style that was made popular by a much earlier Etturan King, with various structures built off a central shaft. During construction wooden scaffolding was assembled in the shaft in order to climb from one level to another. Once Prince Delan was entombed the wooden structure was burned away leaving the central shaft with no easy means of accessing the other portions of the complex.
Much to the chagrin of anyone exploring the site now, sections of the tombs have collapsed, and foul beasts have moved into the bottom of the shaft and live in the walls down there making anything that dangles down to the bottom a danger.
Grab the 1200 dpi version of this map from the blog post at https://rpgcharacters.wordpress.com/2018/09/03/prince-delans-shaft-tomb/