Penance is a unique, prototype sniper rifle that was owned by Psalm.
The sniper rifle was created by the Ministry of Wartime Technology and the Ministry of Arcane Scienes, specifically to be used by unicorn snipers on the front lines. Psalm carried Penance throughout her military career and after The Last Day.
The weapon and Psalm's body armor were sealed inside a locker. Blackjack recovered these from Miramare whilst she was forcibly controlled by The Goddess and kept them once she was free of the Goddess.
Penance is a highly powerful Sniper rifle, that fired 50 caliber rounds. The sniper rifle had a wide range of ammunition types, including explosive anti-personnel, armor penetrating and Dragonkiller rounds. The weapon was also magically augmented to be used by magic users, specifically unicorns.