Captain Jack was once a Time Agent, or pretends to be one.
Captain Jack wears a vortex manipulator.
Dorium Maldovar sold River a vortex manipulator “fresh off the wrist of a handsome Time Agent.”
Dorium Maldovar works with the Headless Monks from time to time.
The Headless Monks decapitate people.
The Face of Boe is a head with no body.