Halsey was a Roonan male Jedi Master active during the Clone Wars. At least one year into the war, Halsey along with his Nautolan Padawan Knox, was dispatched to the Temple of Eedit on the planet of Devaron to defend it from the Separatist Droid Army. Halsey and his Padawan were both killed at the temple by the Dathomirian Zabrak Savage Opress, Count Dooku's new apprentice.