Onyx City

Onyx City is a location that appears in the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics. It is a city in Silver's future, 200 years past the time of Sonic the Hedgehog on Sonic's World. It is a dystopian metropolis ruled over by the City Council and their Civil Protection Robots.

History
At some point, the people of Onyx City were apparently split into different work groups with various assigned colors and shifts. The people clearly disliked the order of their society but seemed unable or unwilling to oppose it, presumably because of the City Council's Civil Protection Robots and other technology.

Trivia

 * Onyx City's name is presumably derived from Onyx Island. It is unconfirmed however, whether this city is on Onyx Island.