Night's Master by Tanith Lee

Mighty, Ruler of Men and Brother of the Gods, whose equal is
not to be found under Heaven.”
    The people marveled at this, and trembled, expecting any moment for the
gods to strike the cities with plague or thunderbolt because of this blasphemy.
But the gods, in those days, regarded the deeds of men much as men have always
regarded the antics of very small children. So there was little danger from the
serene country of Upperearth, where sublime indifference no doubt continued.
Danger there was, but it had another shape.
    It had become a whim of Zorashad’s, when he sat and feasted at night with
his lords, to have brought in and set facing him at the table, a tall chair
carved from bone. This he called the Chair of Uncertainty. Anyone might sit in
it, rich man, prince or beggar, freeman or slave, even the murderer and the
thief might sit down at the king’s table, eat the choicest fare off plates of
gold and drink the finest of wines from crystal cups, and no one could restrain
them or bring them to justice. That was Zorashad’s decree. But at the end of
the feast Zorashad would do to them whatever he wished—either good or evil,
according to his mood; for this resembled, Zorashad declared, the uncertainty
that the gods visited on man during his life, not to know whether pleasure or
hurt, humiliation or triumph or annihilation was his lot. Some who sat in the
bone chair might be fortunate; the god-king would give them precious metal or
gems to take away. They would go out blessing him, glad they had risked their
luck. A few Zorashad might have sewn up in the skin of a wild ass and driven
braying through the streets under the lash till dawn. Others he would condemn
to the axe. It made no difference what the guest’s status might be, or his
deserts. Sometimes the high-born or the virtuous died horribly while the
murderer ran off laughing, with a cap full of emeralds. It was a chair to
gamble in, and most of the gamblers were desperate men, who considered anything
better than life as they were forced under their circumstances to live it. Yet
occasionally, a sage would come, thinking he could outwit the king and so grow
famous in the land. Several were the heads they left behind, spiked on his
gate. Generally, it may be supposed, the chair of bone stood empty.
    One evening, just after sunset, a stranger entered the city of Zojad, a
tall man, shrouded in a black cloak. He passed as quietly as a shadow through
the streets, but when he came to the doors of the palace where the guards stood
with crossed spears, the king’s hounds began to howl from their kennels, the
horses to stamp and whinny in the stables and the falcons to screech in the
mews. The guards, alarmed, glanced about them hurriedly; when they looked back
at the street, the stranger had vanished.
    He was in Zorashad’s splendid hall. The brilliance of two thousand
candles played over his cloak and could not pierce it. He came up the room, and
the minstrel girls fell quiet to watch him pass, even the gorgeous birds in
their cages of gold stopped singing: they put their heads under their wings as
if they felt the approach of winter. The stranger halted before King Zorashad’s
table.
    “I ask a boon, O king,” said he. “To sit in the Uncertain Chair.”
    Zorashad laughed. He was pleased at this unexpected diversion.
    “Sit and welcome,” he said. And he called for basins of rosewater for the
guest to dip his hands, and for the best roasts and vegetables to be given him,
and for wines like ruby or topaz to be poured in his goblet.
    Then the stranger drew back the fold of the cloak which had concealed his
face. There was not one who saw him who did not wonder at his extraordinary
handsomeness. His hair was blue-black like the night, his eyes like two black
suns. He smiled, but the smile was somehow unpleasing. He lightly caressed the
head of the king’s favorite hound and it slunk away and fell down in a corner.
    “O king,” he said in his voice that was like