Moonrise is a one-handed sword in NieR, given to you by a guard in the Southern Plains, after saving him from Shades. This occurs as part of the main story, so it is unmissable.
"A weapon owned by a blind swordsman. The blade shines in darkness, making the owner easy to spot."
There is a legend of a blade that cooled an entire country wrapped in a hellish conflagration. Out of the misery of the endless flames came the people's savior: a sword, surrounded by thousands and thousands of statues made entirely out of ice.
A man searching for the world's legendary weapons came across the sword. He bundled the sword tightly in a long roll of cloth, and took it in hand. But as he placed the sword in his pack and left, unbeknownst to him, the sword began to freeze the cloth, and soon froze him too.
A priestess traveling the world came across the sword. She offered a prayer to the gods, and attempted to draw the sword. But frost quickly spread from her fingertip, to her arm, and all across her body. As she cursed the gods she had invoked, the sword froze her too.
A slave woman, working in a cave, came across the sword. Hoping to escape her painful life forever, she gripped the handle of the sword and drew it out. But, neither did she freeze, nor was she able to thrust it into her breast. The blade's edge gleamed in the moonlight as she was beaten that night by her quickly freezing master.