- "Daring Rescues Our Specialty"
- ―The Dendarii catch-phrase[src]
The DFMF originated as a fictional fleet dreamed up by the seventeen-year-old Miles Naismith Vorkosigan, who impersonated a Betan mercenary admiral to win the Tau Verde Ring war. It eventually incorporated the Oseran Free Mercenary Fleet to its ranks ship by ship, starting with the Ariel. When Vorkosigan was forced to abandon the fleet to face a treason trial, the Dendarii were left under the command of Baz Jesek and became more of a legitimate organization.
The fleet was briefly taken over by Yuan Oser and became the Oseran Mercenaries again. However, Vorkosigan (playing the role of "Admiral Naismith") reclaimed the fleet at age twenty. Oser died during the War of the Hegen Hub, and Vorkosigan's control of the Dendarii was uncontested thereafter. Under his command, the Dendarii became a secret arm of Barrayaran Imperial Security and performed numerous highly covert actions on behalf of the planet Barrayar, including a high-profile rescue of ten thousand Marilacan prisoners of war from Dagoola IV. Nearly twelve years after he founded the fleet, Naismith was forced to relinquish command of the fleet when he developed a seizure disorder. Command passed to Naismith's subordinate Elli Quinn.
The Dendarii Free Mercenary Fleet was a relatively small organization. During the Tau Verde Ring war, when it was called the Oseran Free Mercenary Fleet, the DFMF consisted of 19 warships and approximately three thousand personnel. During the War of the Hegen Hub, the DFMF consisted of five thousand personnel. Its strength was assessed as less than a dozen warships in all.
- Unnamed RG 132-class freighter
- Ariel - a fast cruiser, Captain Bel Thorne commanding
- Triumph - a pocket dreadnought, Captain Auson commanding
- Peregrine - Captain Elena Bothari-Jesek commanding
- Jayhawk - owned and commanded by Captain Truzillo
- Sharkbait One and Sharkbait Three - the jumpscouts
- Three Illyrican-built units, that replaced Triumph, Jayhawk and D-16
- Twelve personnel shuttles (originally fourteen) that held 200 people when not too over-filled. They were not named, but had designators including B-7, A7, and A-4.
- The Triumph had fighter shuttles as well, these were designated simply with numbers, as in "fighter shuttle 5".