A hive city and capital of Scintilla.
The city itself is home to over 12 billion people, and sits on the western shore of the Sibellian Sea. It is a vast mixture of decreipt and the magnificent with many of its tall towers overshadowing the dark and polluted underhive at its base.
The hive is split into many sectors, labelled in the format AA-00-A1, which spreads its great length. The Hive runs along the Sibellian coast and is far longer than it is wide, though for a city of 12,000,000,000 it is still vast in every direction.
Hive Sibellius survives a lot of the polluted weather that sweeps across Scintilla thanks to the ancient weather control satellites that ring the planet. Though maintained by the Adeptus Mechanicus, the technology in these satellites is no longer known throughout the Empire and their ability to mitigate the worst of the acid rain and storms on the hives and their surrounding lands has lead to the continued strength of this hive world.