Protectors of Emerald City
Emerald City has an extensive sewer system. It can be used to get from virtually anywhere to anywhere if one knows enough about its layout, apart from not crossing the Rhine River.
Sewer workers need to be constantly on the lookout due to the more dangerous creatures that inhabit it, in comparison to what one would normally find in a sewer system. For example, the sewers are inhabited by larger and more vicious rats and bats, as well as the occasional alligator or lethal fungal growth. Occasionally strange, unidentified creatures are reported to have been seen in the sewers by city workers.