Mindsword's Story — Fred Saberhagen

Long ago, the gods forged Twelve Swords of Power and threw them on the gameboard of life for men to scramble over. But they forged too well; the Swords could kill the gods themselves.

Now the great Mindsword reenters the world of men, bringing others' mindless devotion to him who wields it: Prince Murat of Culm, who intends to give it to Princess Kristin of Tasavalta. But first he draws it--and receives worship from his own son, from the princess herself, and from a horrifying "ally."

It is up to Prince Mark of Tasavalta: his wife and kingdom, and the world, all may be lost to the Mindsword.