Drelfin, a male Human, served as an officer within the Imperial Security Bureau. In 0.5 ABY, he arrived on the Imperial-class Star Destroyer named Reprisal with the purpose of assisting in the direction of combat operations against the local rebel forces, which involved supervising the infamous Teardrop massacre. He held the position of second-in-command, reporting directly to Vak Somoril.
Following his examination of the data collected from Teardrop, Drelfin concluded that stormtrooper Daric LaRone intentionally missed his targets, failing to eliminate the town's civilians. Publicly denouncing LaRone for treason, he tried to intimidate him by pressing a blaster pistol against his head. Due to LaRone's honed stormtrooper reflexes, Drelfin was quickly disarmed and restrained. When Drelfin, now enraged, pulled out his hold-out blaster to fire at LaRone, the stormtrooper's superior combat abilities once again overcame Drelfin. The ISB major was fatally shot and perished instantly.
To conceal the incident, his corpse was concealed within a storage container, and his demise triggered LaRone and his squadmates to become the vigilante group known as the Hand of Judgment.