Reserves, also known as Back-ups, are Rainbow Operatives that appear in many installments of the Tom Clancy's Rainbow Six Franchise. They are made available to players once they have lost a large amount of named operatives in a playthrough.
Reserves are the soldiers without nation and name. Their flag is that of the UN, meaning that their serve under the UN and NATO council. Reserves have all specialties, because they are trained for every possible situation that a counter terrorism agent can encounter. Due to being faceless operatives, each Reserve has random statistics that vary from one another.
- In Tom Clancy's Rainbow Six 3: Raven Shield, Back-Ups have medical history tabs, despite having no biographies.