Sword of Necessary Evil

 is a weapon in SINoALICE.

Weapon Story
Despite being held by both just and unjust alike, the sword had nothing to do with good or evil.

It simply echoed the feelings of its owner and granted them power.

So when a boy who sought harmony came into possession of the sword, the world was all but certain to be at peace.

But because the sword had a twin, he couldn't help but wonder what would happen if the other object fell into the wrong hands.

The war between good and evil continued...

Until history took an unexpected turn.

It occurred to the boy that, for good to exist, the world needed evil.

So the boy defeated all evil, and hammered the twin swords into one. From then on, he dedicated his life to keeping a precarious balance between good and evil, allowing both to prosper but neither to triumph.