There are a series of tunnels that run under Sacramento. These tunnels were originally the streets of Sacramento before they were raised above sea level to avoid flooding. Historically, the tunnels had served as opium dens, brothels and possibly for ritualistic activity at some point. Several business owners with access to the tunnels have reported an extremely menacing energy and strange noises coming from the tunnels, and went so far as to hire a paranormal investigator.
A great article about the Undercity may be found here.
The underground is rumored to be the lair of the remaining Black Court Vampires, their thralls, and their Ghoul servants. The tunnels and passages are more widespread than the above article states. Over the decades, the underground areas have been excavated and chambers and rooms have been built and expanded. Some areas extend well beyond the original foundations of the city, and the Black Court Vampires
Theme or Threat
ASPECT: DO NOTSTRAYFROMTHETOUR
Archibald Cyrus Breen Black Court Vampire. Cy Breen is one of the last remaining specimens of Black Court Vampires left in Northern California. He has a stronghold somewhere underground, accessible only through the Undercity.