Chief Inspector Primus Churchill was the leader of the Ship's Watch (Internal Security) on the Pathfinder Ship Pegasus . He was a native of the planet Republic , and a member of the Notorium, the Republic Secret Security Service (a.k.a. 'The Centurions'), where his codename was "Bellisarius.'

InBook 02: EdenWorld , Churchill/Bellisarius, assisted in the search for Trajan Lear in the UnderDecks of Pegasus when he was kidnapped during his walkabout.

In Book 04: Winter, Churchill ordered his subordinate Sukhoi was sent to the surface of the planet Winter to assist in the investigation of the murder of Clinton Manchester, under orders from Goneril Lear.

InBook 06: Crucible , Churchill was ordered (as a Centurion) by Geoneril Lear to eliminate Keeler as the commander of Pegasus. He conveyed these orders to his subordinate, Specialist Sukhoi. They were then ordered by Bill Keeler (as the ship's watch) to take the mutinous Goneril Lear into custody. He informed Sukhoi that loyalty to the Notorium trumped all other orders. He left the ship for Lexington Keeler during the crew split.

He was often ridiculed by the stowaway, John Hunter, as a homosexual.