Klar was a lieutenant and a TIE/LN starfighter pilot during the Galactic Civil War. He served aboard the Admonitor, a Star Destroyer under the command of Grand Admiral Thrawn. Assigned to map the Unknown Regions, the ship came across a craft belonging to the Ebruchi.
Klar, after being recommended by Captain Dagon Niriz as especially calm under fire, was sent to the command ship of Creysis, an Ebruchi leader, ostensibly as a TIE fighter escort for the Council of Colonists. In fact, Creysis intended to take them hostage. Knowing this, Thrawn had Klar's TIE fighter stripped of most of its advanced technology in order to deceive the Ebruchi as to the technological level of the Empire.
In on Thrawn's plan, Klar allowed his TIE to fall behind when the escort was attacked. It was disabled and he was captured. In the hands of the Ebruchi, Klar remained calm under interrogation until, his plans in place, Thrawn issued the order for a squad of stormtroopers to blast their way out of hiding places on the Zeta-class shuttle and rescue the prisoners. Klar was safely returned to the Admonitor.