• Both of them are built on top of ancient religous ruins from pagan natives (Druid people for DOTN and and the Native Americans who worship the MWZ Worm in SV)
• The mansions are haunted by the ghosts of people throughout history (DOTN has ghosts from as far as the 1400s due to the 3 Knights and SV has ghosts from as far the 1700s)
• Both places are known to have a cults live in it at some point (DOTN had a revived druid cult founded by a owner and Shem cult founded SV mansion)
It's funny because Rhodes mansion also technically exists in the DA universe