The Castlerose Agency was a group of assassins-for-hire, working in the Divine Fleet. The head of the organisation is Miss's Castlerose.
Castlerose is notable for the ability to transfer its agents from one body to another, using the Castlerose Apparatus. This happens automatically when an agent dies, but may also be possible at other times. This grants Castlerose agents an additional level of cover and anonymity, above that which they might otherwise possess.