During the battle for the planet Ryloth, Admiral Dao commanded a fleet of the Galactic Republic's Open Circle Armada. The grouping of starships served as a relief supply fleet for the people of Ryloth and attempted to protect the planet, which had fallen under a blockade and ground invasion launched by the Confederacy of Independent Systems. The Separatist naval forces fought and destroyed Dao's fleet above Ryloth, taking Dao with it.
Dao's fleet consisted of at least two Venator-class Star Destroyers, which were destroyed after sustained fire from the Separatist ships.