Ronald Rust, the god’s gift to the enemy, any enemy, and a walking encouragement to desertion. The Rust family had produced great soldiers, by the undemanding standards of ‘Deduct your own casualties from those of the enemy, and if the answer is a positive number, it was a glorious victory’ school of applied warfare. But Rust’s lack of any kind of military grasp was matched only by his high opinion of the talent he in fact possessed only in negative amounts

Terry Pratchett - Nights Watch