Sector Charybdis

Sector Charybdis encompasses the Zoah and N'rrgal planetoids, on the bottom of the map

'Sector Charybdis (also called Sector Charyb) is one of two (named) regions in the Twilight Cage, visited by Sonic and friends during Chapter 7 of Sonic Chronicles: The Dark Brotherhood. The sector is presumably named after, or lends its name to, Prefect Charyb, an advanced Gizoid who serves as the co-commander of the Nocturnus Clan army.

The N'rrgal and the Zoah keep Sector Charybdis in the throes of near-constant warfare, a state of affairs which suits Imperator Ix quite nicely. In the Cyclone spaceship, Sonic visits first the N'rrgal Colony, then the Zoah Colony, managing to collect two Chaos Emeralds (and broker a ceasefire between the aliens to boot).