Sewer-based

About
The term "sewer-based" is one used to describe civilizations, organizations, locations or groups located inside the sewer. A famous example is The Sewer Rebellion. Almost all illegal operations or activities can usually be found in a sewer-based location. They are used for various reasons, such as shelter, protection from the law, supplies, and much more. The Cat Society is a common enemy of sewer-based locations since they are known for attempting to destroy and/or capture the sewer-based locations.