From a fantasy series written by Fred Saberhagen.

Twelve swords were forged by the god Vulcan for the entertainment of the gods - they referred to it as the game. They desired to watch humanity fight over the swords, in amusemen.

Each of the swords had a special power, and a unique name. The twelve were:

There was also The Song of Swords, a little song describing the twelve swords with partial descriptions of their power.

Vulcan made one little mistake in his forging of the swords. They were powerful - so powerful, that they were even stronger than the gods themselves, and the game doesn't stay just a game for very long.