Octagon — Fred Saberhagen

THEY CALL IT "STARWEB"....

Players scattered across the continent are engaged in a game. Each player has certain attributes, including skill, strength, courage, cunning, and daring. Each has his kingdom. Each can ally with or attack any of the others.... Starweb offers seemingly endless opportunities for cunning strategems, ferocious attacks, and adroit betrayals--and because such is the stuff of victory, each player must do his best to bring out his worst in what is, after all, only a game.

But one player seems to have confused the reality of the game with the reality of the world: a player with the attributes of machinelike precision and mechanical ruthlessness. His name is Octagon, and he's out for blood.

Even though he doesn't have any.