Curtana Original

The Curtana Original (カーテナ＝オリジナル) is a sword that was broken by an angel to stop an execution by the royals. It allows the wielder to use the power of the Archangel Michael.

Principles
Unlike the replica, the Curtana Original has the full power of the Archangel Michael. With the sword's blessing, the Knights of England, who had sided with Carrisa, became almost invincible, to the point where the Knight Leader himself completely overpowered Kanzaki Kaori, a powerful Saint in her own right.

Toaru Kagaku no Railgun SS2: Shopping Mall Demonstration
While New Light were in Russia, one of their spiritual items was searching for the Curtana Original, locating it around the time they were preparing to leave.

English Civil War Arc
After the Curtana Original was excavated, New Light transported it to Princess Carissa who, upon receiving it, initiated a coup d'état. Carissa made extensive use of the sword's power during the events which followed, empowering the knights with Telesma and in the battle at Buckingham Palace, fought on even grounds against three Saint-level opponents. Queen Elizard, using the spell "Union Jack", was able to weaken the Curtana by spreading it's power to everyone in Britain, thus ending Carrisa's uprising. The sword was then destroyed by the Imagine Breaker when William Orwell propelled Kamijou Touma at Carissa.