The right hand of the brilliant strategist Darth Decimus, Charnus lacks his superior's gift for cunning. However, he makes up for it with a deep cruelty lurking beneath his cordial and refined exterior. Even among the Sith, his viciousness is remarkable, particularly when interrogating helpless prisoners.
His penchant for extracting information has served him well, as he is often assigned to investigate secret organizations and societies within the Sith that might seek to bring the Empire down. His methods are effective, and his success at rooting out and executing traitors is largely responsible for his current position.
Numerous innocent individuals have suffered at his hands as well, but he has always managed to keep the collateral damage of his investigations to an acceptable level.