A hard-bitten Ceres detective who treats the station's collapse as the moment to perform private cleanup beyond the law.
Octavia Muss continues working ordinary sexual-assault and murder cases with Miller while news of the Donnager feeds a dangerous new confidence across the Belt. She gives Miller space after his drinking and is prepared to use him for interrogation theater if necessary, but her practical focus remains on the cases in front of them.
When Earth abruptly abandons its oversight of Ceres, Muss accepts the change without surprise. She tells Miller she has a stop to make near the station core, invoking the rapist from her former work whom the police could never quite catch. The next morning she is late with only the word “Cleanup” in her message. Her absence suggests that the collapse of formal authority has turned an old private threat into something she intends to settle herself.
Muss is a Belter woman with a weathered impassive face, tired observant eyes, and practical Star Helix detective clothes. Her hair is sometimes unkempt from exhaustion, but she carries herself with professional steadiness.
Muss is a station detective whose disciplined indifference to the system's failures becomes dangerous resolve when that system loses authority.