Aegis

The Aegis is the cause of the eternal night over Camora and the only thing standing between the city and the Stars. Its darkness is absolute, and even though it's only said to be about 10' thick its absolute lightlessness makes it impenetrable to the Stars.

The Aegis was put up before the city was built, and signified the end of the Ashen War and the Camoran victory. Thanks to the Aegis, the city continues to live in peace.