Law enforcement authorities long ago gave up trying to keep order in the vast tracts of land snaking beneath the city. These places are teeming with supernaturals, even during the day when light-sensitive creatures have no other option but to skulk about in the tunnels. They have their own rules, their own laws...though there are not many. Those without business down below ought to beware....the police are not going to help you if you stray into the Undercity. You are on your own. And if you have no business there, you should probably get out as soon as you can...
The supernaturals that call the Undercity home follow their own set of laws, and rely on personal accountability in keeping order. You may not get arrested for breach of conduct, but you may be shunned by a particular group for making them look bad.
1.) What happens in the Undercity, stays in the Undercity. If you are a supernatural hiding your true nature on the surface and choose to reveal yourself down below, Undercity dwellers are bound by honor not to reveal your nature. It's presumed that any humans you bring in as a supernatural can be vouched for to follow the law. That doesn't mean you -can't- rat someone out or blackmail them to keep the secret, it just won't be received well by your fellow supernaturals. :)
2.) "True Forms" are allowed at all times. If you mostly use a false form on the surface (either cloaked demons or vampires made up to look human, etc), this is the place to take the mask off and let your true colors show.
3.) Disagreements between individuals shall be settled between those individuals, without clan or group involvement.
4.) If you kill something, clean it up. We don't care to steep in filth.
5.) If you commit a crime on the surface that attracts the eyes of The Law, you are on your own. There will be no safe harbor here.
6.) Any violation of the Undercity laws will be brought before the Undercity Council, and you may be cast out either temporarily or permanently.
Everyone is -welcome- down in the Undercity, but you do need to be aware that the laws that govern the main city do not apply down here. If you've got a shiny and a demon wants it...there's nothing the police can do to get it back if you get robbed. If a vampire lures you down here...you get the idea. Consent rules still apply. You don't have to accept any roleplay you don't want. But this is literally the dark underbelly of the city, so pretty much expect things to be fairly lawless down here.
The crypts, the sewers, the tunnels (with Hellfire and other places), and the caves all are part of the Undercity. Pretty much...if it's underground, it counts.